Browsing by Author "Yadav, Ram Manohar"

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    Functional wood for carbon dioxide capture
    (Cell Press, 2023) Roy, Soumyabrata; Philip, Firuz Alam; Oliveira, Eliezer Fernando; Singh, Gurwinder; Joseph, Stalin; Yadav, Ram Manohar; Adumbumkulath, Aparna; Hassan, Sakib; Khater, Ali; Wu, Xiaowei; Bollini, Praveen; Vinu, Ajayan; Shimizu, George; Ajayan, Pulickel M.; Kibria, Md Golam; Rahman, Muhammad M.
    With increasing global climate change, integrated concepts to innovate sustainable structures that can multiaxially address CO2 mitigation are crucial. Here, we fabricate a functional wood structure with enhanced mechanical performance via a top-down approach incorporating a high-performance metal-organic framework (MOF), Calgary framework 20 (CALF-20). The functional wood with 10% (w/w) CALF-20 can capture CO2 with an overall gravimetric capacity of 0.45 mmol/g at 1 bar and 303 K that scales linearly with the MOF loading. Interestingly, the functional wood surpasses the calculated normalized adsorption capacity of CALF-20 stemming from the mesoporous wood framework, pore geometry modulation in CALF-20, and favorable CO2 uptake interactions. Density functional theory (DFT) calculations elucidate strong interactions between CALF-20 and the cellulose backbone and an understanding of how such interactions can favorably modulate the pore geometry and CO2 physisorption energies. Thus, our work opens an avenue for developing sustainable composites that can be utilized in CO2 capture and structural applications.
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    Regulation of functional groups on graphene quantum dots directs selective CO2 to CH4 conversion
    (Springer Nature, 2021) Zhang, Tianyu; Li, Weitao; Huang, Kai; Guo, Huazhang; Li, Zhengyuan; Fang, Yanbo; Yadav, Ram Manohar; Shanov, Vesselin; Ajayan, Pulickel M.; Wang, Liang; Lian, Cheng; Wu, Jingjie
    A catalyst system with dedicated selectivity toward a single hydrocarbon or oxygenate product is essential to enable the industrial application of electrochemical conversion of CO2 to high-value chemicals. Cu is the only known metal catalyst that can convert CO2 to high-order hydrocarbons and oxygenates. However, the Cu-based catalysts suffer from diverse selectivity. Here, we report that the functionalized graphene quantum dots can direct CO2 to CH4 conversion with simultaneous high selectivity and production rate. The electron-donating groups facilitate the yield of CH4 from CO2 electro-reduction while electron-withdrawing groups suppress CO2 electro-reduction. The yield of CH4 on electron-donating group functionalized graphene quantum dots is positively correlated to the electron-donating ability and content of electron-donating group. The graphene quantum dots functionalized by either –OH or –NH2 functional group could achieve Faradaic efficiency of 70.0% for CH4 at −200 mA cm−2 partial current density of CH4. The superior yield of CH4 on electron-donating group- over the electron-withdrawing group-functionalized graphene quantum dots possibly originates from the maintenance of higher charge density of potential active sites (neighboring C or N) and the interaction between the electron-donating group and key intermediates. This work provides insight into the design of active carbon catalysts at the molecular scale for the CO2 electro-reduction.