Materials Science and NanoEngineering Publications

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Reversible non-volatile electronic switching in a near-room-temperature van der Waals ferromagnet
(Springer Nature, 2024) Wu, Han; Chen, Lei; Malinowski, Paul; Jang, Bo Gyu; Deng, Qinwen; Scott, Kirsty; Huang, Jianwei; Ruff, Jacob P. C.; He, Yu; Chen, Xiang; Hu, Chaowei; Yue, Ziqin; Oh, Ji Seop; Teng, Xiaokun; Guo, Yucheng; Klemm, Mason; Shi, Chuqiao; Shi, Yue; Setty, Chandan; Werner, Tyler; Hashimoto, Makoto; Lu, Donghui; Yilmaz, Turgut; Vescovo, Elio; Mo, Sung-Kwan; Fedorov, Alexei; Denlinger, Jonathan D.; Xie, Yaofeng; Gao, Bin; Kono, Junichiro; Dai, Pengcheng; Han, Yimo; Xu, Xiaodong; Birgeneau, Robert J.; Zhu, Jian-Xin; da Silva Neto, Eduardo H.; Wu, Liang; Chu, Jiun-Haw; Si, Qimiao; Yi, Ming; Rice Center for Quantum Materials
Non-volatile phase-change memory devices utilize local heating to toggle between crystalline and amorphous states with distinct electrical properties. Expanding on this kind of switching to two topologically distinct phases requires controlled non-volatile switching between two crystalline phases with distinct symmetries. Here, we report the observation of reversible and non-volatile switching between two stable and closely related crystal structures, with remarkably distinct electronic structures, in the near-room-temperature van der Waals ferromagnet Fe5−δGeTe2. We show that the switching is enabled by the ordering and disordering of Fe site vacancies that results in distinct crystalline symmetries of the two phases, which can be controlled by a thermal annealing and quenching method. The two phases are distinguished by the presence of topological nodal lines due to the preserved global inversion symmetry in the site-disordered phase, flat bands resulting from quantum destructive interference on a bipartite lattice, and broken inversion symmetry in the site-ordered phase.
Revealing the impact of ammonium ions from different low-dimensional perovskite structures on the film formation and degradation mechanism of FAPbI3 via sequential deposition
(AIP Publishing LLC, 2024) Wang, Yafei; Yuan, Shihao; Feng, Rongsen; Diao, Zecheng; Huang, Jie; Liao, Jiacai; Sidhik, Siraj; Shuai, Xinting; Wang, Meicong; Zou, Tao; Liang, Zhongwei; Zhang, Ting; Mohite, Aditya D.; Li, Shibin
In recent years, the organic–inorganic hybrid perovskite community has been widely employed as the photo-active layer in optical-electronic devices. The black α-phase formamidinium lead iodide (FAPbI3) is the most popular perovskite for realizing high-efficiency solar cells due to its suitable bandgap. However, the issue of stability is also a concern in the research on FAPbI3 solar cells. In this study, different ammonium ions, such as butylamine (BA), guanidine (GA), and butylene diamine (BDA), which are commonly used to construct two-dimensional perovskites, including Ruddlesden–Popper, Dion–Jacobson, and alternating cations in the interlayer space, respectively, were introduced in the fabrication of FAPbI3 using a sequential deposition method. Several structures of PbI2 precursor films were formed by introducing the aforementioned ions, which exhibited different arrangements and connection modes in lead iodides. BA-PbI2 precursor films exhibited higher specific surface areas, which were beneficial to the diffusion, ion exchange, and sequential reaction of FA+. The BDA-PbI2 precursor film slowed down the sequential reaction of FAPbI3 because of reduced van der Waals bonds. The nucleation dynamics and degradation processes of perovskites were deeply investigated in this study. Solar cells based on BA-PbI2, GA-PbI2, and BDA-PbI2 were also fabricated.
Spin disorder control of topological spin texture
(Springer Nature, 2024) Zhang, Hongrui; Shao, Yu-Tsun; Chen, Xiang; Zhang, Binhua; Wang, Tianye; Meng, Fanhao; Xu, Kun; Meisenheimer, Peter; Chen, Xianzhe; Huang, Xiaoxi; Behera, Piush; Husain, Sajid; Zhu, Tiancong; Pan, Hao; Jia, Yanli; Settineri, Nick; Giles-Donovan, Nathan; He, Zehao; Scholl, Andreas; N’Diaye, Alpha; Shafer, Padraic; Raja, Archana; Xu, Changsong; Martin, Lane W.; Crommie, Michael F.; Yao, Jie; Qiu, Ziqiang; Majumdar, Arun; Bellaiche, Laurent; Muller, David A.; Birgeneau, Robert J.; Ramesh, Ramamoorthy; Rice Advanced Materials Institute
Stabilization of topological spin textures in layered magnets has the potential to drive the development of advanced low-dimensional spintronics devices. However, achieving reliable and flexible manipulation of the topological spin textures beyond skyrmion in a two-dimensional magnet system remains challenging. Here, we demonstrate the introduction of magnetic iron atoms between the van der Waals gap of a layered magnet, Fe3GaTe2, to modify local anisotropic magnetic interactions. Consequently, we present direct observations of the order-disorder skyrmion lattices transition. In addition, non-trivial topological solitons, such as skyrmioniums and skyrmion bags, are realized at room temperature. Our work highlights the influence of random spin control of non-trivial topological spin textures.
Strong nonlinear optical processes with extraordinary polarization anisotropy in inversion-symmetry broken two-dimensional PdPSe
(Springer Nature, 2024) Zhu, Song; Duan, Ruihuan; Xu, Xiaodong; Sun, Fangyuan; Chen, Wenduo; Wang, Fakun; Li, Siyuan; Ye, Ming; Zhou, Xin; Cheng, Jinluo; Wu, Yao; Liang, Houkun; Kono, Junichiro; Li, Xingji; Liu, Zheng; Wang, Qi Jie
Nonlinear optical activities, especially second harmonic generation (SHG), are key phenomena in inversion-symmetry-broken two-dimensional (2D) transition metal dichalcogenides (TMDCs). On the other hand, anisotropic nonlinear optical processes are important for unique applications in nano-nonlinear photonic devices with polarization functions, having become one of focused research topics in the field of nonlinear photonics. However, the strong nonlinearity and strong optical anisotropy do not exist simultaneously in common 2D materials. Here, we demonstrate strong second-order and third-order susceptibilities of 64 pm/V and 6.2×10−19 m2/V2, respectively, in the even-layer PdPSe, which has not been discovered in other common TMDCs (e.g., MoS2). Strikingly, it also simultaneously exhibited strong SHG anisotropy with an anisotropic ratio of ~45, which is the largest reported among all 2D materials to date, to the best of our knowledge. In addition, the SHG anisotropy ratio can be harnessed from 0.12 to 45 (375 times) by varying the excitation wavelength due to the dispersion of $${\chi }^{(2)}$$values. As an illustrative example, we further demonstrate polarized SHG imaging for potential applications in crystal orientation identification and polarization-dependent spatial encoding. These findings in 2D PdPSe are promising for nonlinear nanophotonic and optoelectronic applications.
Emergency of per- and polyfluoroalkyl substances in drinking water: Status, regulation, and mitigation strategies in developing countries
(Elsevier, 2024) Adewuyi, Adewale; Li, Qilin; NSF Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment
The detection of per- and polyfluoroalkyl substances (PFAS) in water presents a significant challenge for developing countries, requiring urgent attention. This review focuses on understanding the emergence of PFAS in drinking water, health concerns, and removal strategies for PFAS in water systems in developing countries. This review indicates the need for more studies to be conducted in many developing nations due to limited information on the environmental status and fate of PFAS. The health consequences of PFAS in water are enormous and cannot be overemphasized. Efforts are ongoing to legislate a national standard for PFAS in drinking water. Currently, there are few known mitigation efforts from African countries, in contrast to several developing nations in Asia. Therefore, there is an urgent need to develop economically viable techniques that could be integrated into large-scale operations to remove PFAS from water systems in the region. However, despite the success achieved with removing long-chain PFAS from water, more studies are required on strategies for eliminating short-chain moieties in water.
Interplay between Point and Extended Defects and Their Effects on Jerky Domain-Wall Motion in Ferroelectric Thin Films
(American Physical Society, 2024) Bulanadi, Ralph; Cordero-Edwards, Kumara; Tückmantel, Philippe; Saremi, Sahar; Morpurgo, Giacomo; Zhang, Qi; Martin, Lane W.; Nagarajan, Valanoor; Paruch, Patrycja; Rice Advanced Materials Institute
Defects have a significant influence on the polarization and electromechanical properties of ferroelectric materials. Statistically, they can be seen as random pinning centers acting on an elastic manifold, slowing domain-wall propagation and raising the energy required to switch polarization. Here we show that the “dressing” of defects can lead to unprecedented control of domain-wall dynamics. We engineer defects of two different dimensionalities in ferroelectric oxide thin films—point defects externally induced via He2+ bombardment, and extended quasi-one-dimensional 𝑎 domains formed in response to internal strains. The 𝑎 domains act as extended strong pinning sites (as expected) imposing highly localized directional constraints. Surprisingly, the induced point defects in the He2+ bombarded samples orient and align to impose further directional pinning, screening the effect of 𝑎 domains. This defect interplay produces more uniform and predictable domain-wall dynamics. Such engineered interactions between defects are crucial for advancements in ferroelectric devices.
Emergence of microplastics in African environmental drinking water sources: A review on sources, analysis and treatment strategies
(Elsevier, 2024) Adewuyi, Adewale; Li, Qilin; NSF Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment
The emergence of microplastics (MPs) as microcontaminants in environmental drinking water sources is a problem in Africa that requires immediate action. Therefore, this review focused on understanding the sources of MPs in African water systems, treatment strategies, analytical methods for identification and quantification, and Africa's pollution index. From the findings, the source of MPs in African water systems was attributed to unregulated importation of plastic products, poor waste management, lack of awareness, poor environmental value system and the inability of local polymer industries to adjust to new policies on plastic management. Most studies identified microfibers and microbeads to be the primary sources of plastics that break down to MPs in African drinking water sources, with polystyrene (PS), polypropylene (PP), and polyethylene (PE) being frequently detected. Current methods for identification, and quantification of MPs in most studies conducted in Africa were not developed in Africa but was adopted from developed countries and, in some cases, modified to meet specific analytical requirements. More studies are necessary for in-depth understanding of the fate and pollution index of MP in African environmental water systems. Furthermore, the interaction between MP and other pollutants in the water system still needs to be better understood. This review suggests membrane and rapid sand filtration methods as promising methods that may be considered for removing MPs from water systems in Africa.
Quantum simulation of an extended Dicke model with a magnetic solid
(Springer Nature, 2024) Marquez Peraca, Nicolas; Li, Xinwei; Moya, Jaime M.; Hayashida, Kenji; Kim, Dasom; Ma, Xiaoxuan; Neubauer, Kelly J.; Fallas Padilla, Diego; Huang, Chien-Lung; Dai, Pengcheng; Nevidomskyy, Andriy H.; Pu, Han; Morosan, Emilia; Cao, Shixun; Bamba, Motoaki; Kono, Junichiro
The Dicke model describes the cooperative interaction of an ensemble of two-level atoms with a single-mode photonic field and exhibits a quantum phase transition as a function of light–matter coupling strength. Extending this model by incorporating short-range atom–atom interactions makes the problem intractable but is expected to produce new physical phenomena and phases. Here, we simulate such an extended Dicke model using a crystal of ErFeO3, where the role of atoms (photons) is played by Er3+ spins (Fe3+ magnons). Through terahertz spectroscopy and magnetocaloric effect measurements as a function of temperature and magnetic field, we demonstrated the existence of a novel atomically ordered phase in addition to the superradiant and normal phases that are expected from the standard Dicke model. Further, we elucidated the nature of the phase boundaries in the temperature–magnetic-field phase diagram, identifying both first-order and second-order phase transitions. These results lay the foundation for studying multiatomic quantum optics models using well-characterized many-body solid-state systems.
Physics-inspired transfer learning for ML-prediction of CNT band gaps from limited data
(Springer Nature, 2024) Bets, Ksenia V.; O’Driscoll, Patrick C.; Yakobson, Boris I.
Recent years have seen a drastic increase in the scientific use of machine learning (ML) techniques, yet their applications remain limited for many fields. Here, we demonstrate techniques that allow overcoming two obstacles to the widespread adoption of ML, particularly relevant to nanomaterials and nanoscience fields. Using the prediction of the band gap values of carbon nanotubes as a typical example, we address the representation of the periodic data as well as training on extremely small datasets. We successfully showed that careful choice of the activation function allows capturing periodic tendencies in the datasets that are common in physical data and previously posed significant difficulty for neural networks. In particular, utilization of the recently proposed parametric periodic Snake activation function shows a dramatic improvement. Furthermore, tackling a typical lack of accurate data, we used the transfer learning technique utilizing more abundant low-quality computational data and achieving outstanding accuracy on a significantly expanded dataspace. This strategy was enabled by the use of a combination of the Snake and ReLU layers, capturing data periodicity and amplitude, respectively. Hence, retraining only ReLU layers allowed the transfer of the periodic tendencies captured from low-quality data to the final high-accuracy neural network. Those techniques are expected to expand the usability of ML approaches in application to physical data in general and the fields of nanomaterials in particular.
Programmed multimaterial assembly by synergized 3D printing and freeform laser induction
(Springer Nature, 2024) Zheng, Bujingda; Xie, Yunchao; Xu, Shichen; Meng, Andrew C.; Wang, Shaoyun; Wu, Yuchao; Yang, Shuhong; Wan, Caixia; Huang, Guoliang; Tour, James M.; Lin, Jian; Smalley-Curl Institute
In nature, structural and functional materials often form programmed three-dimensional (3D) assembly to perform daily functions, inspiring researchers to engineer multifunctional 3D structures. Despite much progress, a general method to fabricate and assemble a broad range of materials into functional 3D objects remains limited. Herein, to bridge the gap, we demonstrate a freeform multimaterial assembly process (FMAP) by integrating 3D printing (fused filament fabrication (FFF), direct ink writing (DIW)) with freeform laser induction (FLI). 3D printing performs the 3D structural material assembly, while FLI fabricates the functional materials in predesigned 3D space by synergistic, programmed control. This paper showcases the versatility of FMAP in spatially fabricating various types of functional materials (metals, semiconductors) within 3D structures for applications in crossbar circuits for LED display, a strain sensor for multifunctional springs and haptic manipulators, a UV sensor, a 3D electromagnet as a magnetic encoder, capacitive sensors for human machine interface, and an integrated microfluidic reactor with a built-in Joule heater for nanomaterial synthesis. This success underscores the potential of FMAP to redefine 3D printing and FLI for programmed multimaterial assembly.
Oxidized Activated Charcoal Nanozymes: Synthesis, and Optimization for In Vitro and In Vivo Bioactivity for Traumatic Brain Injury
(Wiley, 2024) McHugh, Emily A.; Liopo, Anton V.; Mendoza, Kimberly; Robertson, Claudia S.; Wu, Gang; Wang, Zhe; Chen, Weiyin; Beckham, Jacob L.; Derry, Paul J.; Kent, Thomas A.; Tour, James M.; Smalley-Curl Institute;NanoCarbon Center;Welch Institute for Advanced Materials
Carbon-based superoxide dismutase (SOD) mimetic nanozymes have recently been employed as promising antioxidant nanotherapeutics due to their distinct properties. The structural features responsible for the efficacy of these nanomaterials as antioxidants are, however, poorly understood. Here, the process–structure–property–performance properties of coconut-derived oxidized activated charcoal (cOAC) nano-SOD mimetics are studied by analyzing how modifications to the nanomaterial's synthesis impact the size, as well as the elemental and electrochemical properties of the particles. These properties are then correlated to the in vitro antioxidant bioactivity of poly(ethylene glycol)-functionalized cOACs (PEG-cOAC). Chemical oxidative treatment methods that afford smaller, more homogeneous cOAC nanoparticles with higher levels of quinone functionalization show enhanced protection against oxidative damage in bEnd.3 murine endothelioma cells. In an in vivo rat model of mild traumatic brain injury (mTBI) and oxidative vascular injury, PEG-cOACs restore cerebral perfusion rapidly to the same extent as the former nanotube-derived PEG-hydrophilic carbon clusters (PEG-HCCs) with a single intravenous injection. These findings provide a deeper understanding of how carbon nanozyme syntheses can be tailored for improved antioxidant bioactivity, and set the stage for translation of medical applications.
Non-volatile magnon transport in a single domain multiferroic
(Springer Nature, 2024) Husain, Sajid; Harris, Isaac; Meisenheimer, Peter; Mantri, Sukriti; Li, Xinyan; Ramesh, Maya; Behera, Piush; Taghinejad, Hossein; Kim, Jaegyu; Kavle, Pravin; Zhou, Shiyu; Kim, Tae Yeon; Zhang, Hongrui; Stevenson, Paul; Analytis, James G.; Schlom, Darrell; Salahuddin, Sayeef; Íñiguez-González, Jorge; Xu, Bin; Martin, Lane W.; Caretta, Lucas; Han, Yimo; Bellaiche, Laurent; Yao, Zhi; Ramesh, Ramamoorthy; Rice Advanced Materials Institute
Antiferromagnets have attracted significant attention in the field of magnonics, as promising candidates for ultralow-energy carriers for information transfer for future computing. The role of crystalline orientation distribution on magnon transport has received very little attention. In multiferroics such as BiFeO3 the coupling between antiferromagnetic and polar order imposes yet another boundary condition on spin transport. Thus, understanding the fundamentals of spin transport in such systems requires a single domain, a single crystal. We show that through Lanthanum (La) substitution, a single ferroelectric domain can be engineered with a stable, single-variant spin cycloid, controllable by an electric field. The spin transport in such a single domain displays a strong anisotropy, arising from the underlying spin cycloid lattice. Our work shows a pathway to understanding the fundamental origins of magnon transport in such a single domain multiferroic.
Nondestructive flash cathode recycling
(Springer Nature, 2024) Chen, Weiyin; Cheng, Yi; Chen, Jinhang; Bets, Ksenia V.; Salvatierra, Rodrigo V.; Ge, Chang; Li, John Tianci; Luong, Duy Xuan; Kittrell, Carter; Wang, Zicheng; McHugh, Emily A.; Gao, Guanhui; Deng, Bing; Han, Yimo; Yakobson, Boris I.; Tour, James M.; Applied Physics Program;Smalley-Curl Institute;NanoCarbon Center;Rice Advanced Materials Institute
Effective recycling of end-of-life Li-ion batteries (LIBs) is essential due to continuous accumulation of battery waste and gradual depletion of battery metal resources. The present closed-loop solutions include destructive conversion to metal compounds, by destroying the entire three-dimensional morphology of the cathode through continuous thermal treatment or harsh wet extraction methods, and direct regeneration by lithium replenishment. Here, we report a solvent- and water-free flash Joule heating (FJH) method combined with magnetic separation to restore fresh cathodes from waste cathodes, followed by solid-state relithiation. The entire process is called flash recycling. This FJH method exhibits the merits of milliseconds of duration and high battery metal recovery yields of ~98%. After FJH, the cathodes reveal intact core structures with hierarchical features, implying the feasibility of their reconstituting into new cathodes. Relithiated cathodes are further used in LIBs, and show good electrochemical performance, comparable to new commercial counterparts. Life-cycle-analysis highlights that flash recycling has higher environmental and economic benefits over traditional destructive recycling processes.
Molecular scale nanophotonics: hot carriers, strong coupling, and electrically driven plasmonic processes
(De Gruyter, 2024) Zhu, Yunxuan; Raschke, Markus B.; Natelson, Douglas; Cui, Longji
Plasmonic modes confined to metallic nanostructures at the atomic and molecular scale push the boundaries of light–matter interactions. Within these extreme plasmonic structures of ultrathin nanogaps, coupled nanoparticles, and tunnelling junctions, new physical phenomena arise when plasmon resonances couple to electronic, exitonic, or vibrational excitations, as well as the efficient generation of non-radiative hot carriers. This review surveys the latest experimental and theoretical advances in the regime of extreme nano-plasmonics, with an emphasis on plasmon-induced hot carriers, strong coupling effects, and electrically driven processes at the molecular scale. We will also highlight related nanophotonic and optoelectronic applications including plasmon-enhanced molecular light sources, photocatalysis, photodetection, and strong coupling with low dimensional materials.
Hierarchically porous and single Zn atom-embedded carbon molecular sieves for H2 separations
(Springer Nature, 2024) Hu, Leiqing; Lee, Won-Il; Roy, Soumyabrata; Subramanian, Ashwanth; Kisslinger, Kim; Zhu, Lingxiang; Fan, Shouhong; Hwang, Sooyeon; Bui, Vinh T.; Tran, Thien; Zhang, Gengyi; Ding, Yifu; Ajayan, Pulickel M.; Nam, Chang-Yong; Lin, Haiqing
Hierarchically porous materials containing sub-nm ultramicropores with molecular sieving abilities and microcavities with high gas diffusivity may realize energy-efficient membranes for gas separations. However, rationally designing and constructing such pores into large-area membranes enabling efficient H2 separations remains challenging. Here, we report the synthesis and utilization of hybrid carbon molecular sieve membranes with well-controlled nano- and micro-pores and single zinc atoms and clusters well-dispersed inside the nanopores via the carbonization of supramolecular mixed matrix materials containing amorphous and crystalline zeolitic imidazolate frameworks. Carbonization temperature is used to fine-tune pore sizes, achieving ultrahigh selectivity for H2/CO2 (130), H2/CH4 (2900), H2/N2 (880), and H2/C2H6 (7900) with stability against water vapor and physical aging during a continuous 120-h test.
Highly sensitive 2D X-ray absorption spectroscopy via physics informed machine learning
(Springer Nature, 2024) Li, Zeyuan; Flynn, Thomas; Liu, Tongchao; Liu, Sizhan; Lee, Wah-Keat; Tang, Ming; Ge, Mingyuan
Improving the spatial and spectral resolution of 2D X-ray near-edge absorption structure (XANES) has been a decade-long pursuit to probe local chemical reactions at the nanoscale. However, the poor signal-to-noise ratio in the measured images poses significant challenges in quantitative analysis, especially when the element of interest is at a low concentration. In this work, we developed a post-imaging processing method using deep neural network to reliably improve the signal-to-noise ratio in the XANES images. The proposed neural network model could be trained to adapt to new datasets by incorporating the physical features inherent in the latent space of the XANES images and self-supervised to detect new features in the images and achieve self-consistency. Two examples are presented in this work to illustrate the model’s robustness in determining the valence states of Ni and Co in the LiNixMnyCo1-x-yO2 systems with high confidence.
Combination Nanomedicine Strategy for Preventing High-Risk Corneal Transplantation Rejection
(American Chemical Society, 2024) Meng, Tuo; Zheng, Jinhua; Shin, Crystal S.; Gao, Nan; Bande, Divya; Sudarjat, Hadi; Chow, Woon; Halquist, Matthew Sean; Yu, Fu-Shin; Acharya, Ghanashyam; Xu, Qingguo
High-risk (HR) corneal transplantation presents a formidable challenge, with over 50% of grafts experiencing rejection despite intensive postoperative care involving frequent topical eyedrop administration up to every 2 h, gradually tapering over 6–12 months, and ongoing maintenance dosing. While clinical evidence underscores the potential benefits of inhibiting postoperative angiogenesis, effective antiangiogenesis therapy remains elusive in this context. Here, we engineered controlled-release nanomedicine formulations comprising immunosuppressants (nanoparticles) and antiangiogenesis drugs (nanowafer) and demonstrated that these formulations can prevent HR corneal transplantation rejection for at least 6 months in a clinically relevant rat model. Unlike untreated corneal grafts, which universally faced rejection within 2 weeks postsurgery, a single subconjunctival injection of the long-acting immunosuppressant nanoparticle alone effectively averted graft rejection for 6 months, achieving a graft survival rate of ∼70%. Notably, the combination of an immunosuppressant nanoparticle and an anti-VEGF nanowafer yielded significantly better efficacy with a graft survival rate of >85%. The significantly enhanced efficacy demonstrated that a combination nanomedicine strategy incorporating immunosuppressants and antiangiogenesis drugs can greatly enhance the ocular drug delivery and benefit the outcome of HR corneal transplantation with increased survival rate, ensuring patient compliance and mitigating dosing frequency and toxicity concerns.
Isolated Iridium Sites on Potassium-Doped Carbon-nitride wrapped Tellurium Nanostructures for Enhanced Glycerol Photooxidation
(Wiley, 2024) Kumar, Pawan; Askar, Abdelrahman; Wang, Jiu; Roy, Soumyabrata; Kancharlapalli, Srinivasu; Wang, Xiyang; Joshi, Varad; Hu, Hangtian; Kannimuthu, Karthick; Trivedi, Dhwanil; Bollini, Praveen; Wu, Yimin A.; Ajayan, Pulickel M.; Adachi, Michael M.; Hu, Jinguang; Kibria, Md Golam
Many industrial processes such transesterification of fatty acid for biodiesel production, soap manufacturing and biosynthesis of ethanol generate glycerol as a major by-product that can be used to produce commodity chemicals. Photocatalytic transformation of glycerol is an enticing approach that can exclude the need of harsh oxidants and extraneous thermal energy. However, the product yield and selectivity remain poor due to low absorption and unsymmetrical site distribution on the catalyst surface. Herein, tellurium (Te) nanorods/nanosheets (TeNRs/NSs) wrapped potassium-doped carbon nitride (KCN) van der Waal (vdW) heterojunction (TeKCN) is designed to enhance charge separation and visible-NIR absorption. The iridium (Ir) single atom sites decoration on the TeKCN core-shell structure (TeKCNIr) promotes selective oxidation of glycerol to glyceraldehyde with a conversion of 45.6% and selectivity of 61.6% under AM1.5G irradiation. The catalytic selectivity can reach up to 88% under 450 nm monochromatic light. X-ray absorption spectroscopy (XAS) demonstrates the presence of undercoordinated IrN2O2 sites which improved catalytic selectivity for glycol oxidation. Band energies and computational calculations reveal faile charge transfer in the TeKCNIr heterostructure. EPR and scavenger tests discern that superoxide (O2•−) and hydroxyl (•OH) radicals are prime components driving glycerol oxidation.
Hard carbon anode for lithium-, sodium-, and potassium-ion batteries: Advancement and future perspective
(Elsevier, 2024) Saju, Sreehari K.; Chattopadhyay, Shreyasi; Xu, Jianan; Alhashim, Salma; Pramanik, Atin; Ajayan, Pulickel M.
Due to its overall performance, hard carbon (HC) is a promising anode for rechargeable lithium-, sodium-, and potassium-ion batteries (LIBs, NIBs, KIBs). The microcrystalline structure morphology of HCs facilitates the alkali metal -ion uptake and fast ion intercalation and deintercalation throughout the pores with low-potential intercalation properties. However, the large-scale industrial application of HCs is still lagging because of the first-cycle reversible capacity, which results in low initial Coulombic efficiency (ICE) and voltage hysteresis. This review focuses on the fundamental mechanism of HCs as alkali metal-ion batteries, with the current issues being discussed. This includes the formation of solid electrolyte interphase during the first cycle with low ICE, safety concerns, and improved performances, which are vital for practical applicability. The current state-of-the-art of HC anodes is discussed here with recent literature. Furthermore, the challenges and the corresponding effective strategies to overcome the difficulties related to the commercialization of HCs as rechargeable battery anodes are discussed.
Electrothermal mineralization of per- and polyfluoroalkyl substances for soil remediation
(Springer Nature, 2024) Cheng, Yi; Deng, Bing; Scotland, Phelecia; Eddy, Lucas; Hassan, Arman; Wang, Bo; Silva, Karla J.; Li, Bowen; Wyss, Kevin M.; Ucak-Astarlioglu, Mine G.; Chen, Jinhang; Liu, Qiming; Si, Tengda; Xu, Shichen; Gao, Xiaodong; JeBailey, Khalil; Jana, Debadrita; Torres, Mark Albert; Wong, Michael S.; Yakobson, Boris I.; Griggs, Christopher; McCary, Matthew A.; Zhao, Yufeng; Tour, James M.
Per- and polyfluoroalkyl substances (PFAS) are persistent and bioaccumulative pollutants that can easily accumulate in soil, posing a threat to environment and human health. Current PFAS degradation processes often suffer from low efficiency, high energy and water consumption, or lack of generality. Here, we develop a rapid electrothermal mineralization (REM) process to remediate PFAS-contaminated soil. With environmentally compatible biochar as the conductive additive, the soil temperature increases to >1000 °C within seconds by current pulse input, converting PFAS to calcium fluoride with inherent calcium compounds in soil. This process is applicable for remediating various PFAS contaminants in soil, with high removal efficiencies ( >99%) and mineralization ratios ( >90%). While retaining soil particle size, composition, water infiltration rate, and cation exchange capacity, REM facilitates an increase of exchangeable nutrient supply and arthropod survival in soil, rendering it superior to the time-consuming calcination approach that severely degrades soil properties. REM is scaled up to remediate soil at two kilograms per batch and promising for large-scale, on-site soil remediation. Life-cycle assessment and techno-economic analysis demonstrate REM as an environmentally friendly and economic process, with a significant reduction of energy consumption, greenhouse gas emission, water consumption, and operation cost, when compared to existing soil remediation practices.

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