Periodic Reporting for period 1 - PhotoCatRed (Visible-light-driven Photocatalytic CO2 Reduction to Solar fuels by multinary N-Graphene based Heterostructure Composites)
Reporting period: 2019-08-01 to 2021-07-31
Energy shortage and environment pollution are two critical threats faced by the present society. Carbon dioxide, the well-known greenhouse gas is a major cause of global warming but at same time it is also an abundant resource for hydrocarbon energy fuels. Solar energy driven photocatalytic CO2 reduction into clean chemical energy fuels is a very challenging yet actively pursued research topic due to its high potential for simultaneously solving the energy crisis and environmental issues. In this proposal, we constructed a ternary heterostructure photocatalyst based on N-doped graphene demonstrated high efficiency for photocatalytic CO2 reduction under visible light. It is deduced that N-graphene dominates the generation of solar fuels in this ternary composite system, which should be ascribed to the unique quality of N-graphene as an excellent electron transfer mediator and adsorber for CO2. Notably, this work exhibits new strategy to convert CO2 into chemicals, and new materials to effectively store solar energy as chemical energy. It is an improvement on artificial photosynthesis, and provides a potential way of simultaneously solving the carbon emission and energy shortage problems.
The proposal targets to undertake the following specific challenges:
(A) Design and synthesis of graphene-based heterostructured photocatalyst with rationally designed multicomponents to address the issues of (1) extended visible light response (2) high surface adsorption of CO2 (3) high rate of photogenerated electron-hole transport (4) low rate of photogenerated (e-h) recombination (5) high selectivity for specific hydrocarbon fuel products and (6) low cost.
(B) Design suitable laboratory reactor system to conduct the photocatalytic CO2 conversion studies on the newly synthesized heterostructure photocatalysts under visible light and study the mechanism of the process with help from theoretical/computational methods.
Achievements:
We demonstrate a series of ternary Au@TiO2 decorated N-doped graphene (ANGT-x) nanocomposite photocatalysts successfully synthesized by multistep preparation process, which exhibited significant enhancement in the photocatalytic activity toward solar fuel production with high selectivity for methane. Experimental results corroborated with theoretical DFT studies validated the unique ability quality of N-graphene playing a key role in efficiently reducing the Gibbs free energy of PCO2R reaction kinetics, increasing the binding strength of *COOH intermediate and improves the charge transfer process. In contrast to the conventionally reported binary or catalysts, the synergistic coordination in ANGT facilitated. It is deduced that N-graphene dominates the generation of CH4 in this ternary ANGT2 composite system, which should be ascribed to the unique quality of N-graphene as an excellent electron transfer mediator and adsorber for CO2. Moreover, the ANGT2 heterostructure photocatalyst exhibited the highest Relectron of 742.39 µmol g-1 h-1 for PCO2R under visible light irradiation with favorable cycling stability. The Relectron achieved here is 4 times higher than that of ANGT0 and 60 times higher than of binary AT2. The illustrated mechanism and the enhanced photocatalytic efficiency of ternary ANGT-x nanocomposites paves way for the development of future ternary hybrid solar fuel photocatalysts based on NG.
(A) Design and synthesis of graphene-based heterostructured photocatalyst with rationally designed multicomponents to address the issues of (1) extended visible light response (2) high surface adsorption of CO2 (3) high rate of photogenerated electron-hole transport (4) low rate of photogenerated (e-h) recombination (5) high selectivity for specific hydrocarbon fuel products and (6) low cost.
(B) Design suitable laboratory reactor system to conduct the photocatalytic CO2 conversion studies on the newly synthesized heterostructure photocatalysts under visible light and study the mechanism of the process with help from theoretical/computational methods.
Achievements:
We demonstrate a series of ternary Au@TiO2 decorated N-doped graphene (ANGT-x) nanocomposite photocatalysts successfully synthesized by multistep preparation process, which exhibited significant enhancement in the photocatalytic activity toward solar fuel production with high selectivity for methane. Experimental results corroborated with theoretical DFT studies validated the unique ability quality of N-graphene playing a key role in efficiently reducing the Gibbs free energy of PCO2R reaction kinetics, increasing the binding strength of *COOH intermediate and improves the charge transfer process. In contrast to the conventionally reported binary or catalysts, the synergistic coordination in ANGT facilitated. It is deduced that N-graphene dominates the generation of CH4 in this ternary ANGT2 composite system, which should be ascribed to the unique quality of N-graphene as an excellent electron transfer mediator and adsorber for CO2. Moreover, the ANGT2 heterostructure photocatalyst exhibited the highest Relectron of 742.39 µmol g-1 h-1 for PCO2R under visible light irradiation with favorable cycling stability. The Relectron achieved here is 4 times higher than that of ANGT0 and 60 times higher than of binary AT2. The illustrated mechanism and the enhanced photocatalytic efficiency of ternary ANGT-x nanocomposites paves way for the development of future ternary hybrid solar fuel photocatalysts based on NG.
we have successfully fabricated ternary Au@N-doped graphene decorated-TiO2 (ANGT-x) heterostructure catalysts by a multistep preparation process and demonstrated for solar-light-switched CO2 reduction towards CH4 production with high selectivity using a gas-phase, batch reactor system. Successful formation of the composite was confirmed by XRD, STEM, Raman, and XPS analysis; UV-Vis-DRS, PL, TPR and EIS analysis confirmed improved optical properties and successful charge migration among the catalysts. Meanwhile, Au NPs act as electron sinks to promote catalytic activity; therefore, the optimized sample ANGT2 delivers the highest Relectron of 742.39 µmol g-1 h-1 in 4 h under the visible-light irradiation. Most importantly, the catalytic activity was ≈4 and ≈60 folds higher than ANGT0 and AT2, respectively. The catalyst displayed the photostability of up to 3 cycles. The enhanced catalytic activity and stability of ANGT2 attributed to increased visible light absorption, improved charge separation, and unwanted charge recombination. The post-catalytic analysis also proves that the catalyst’s chemical stability is well enough to use long-term applications. The in-depth photocatalytic CO2 reduction mechanism over the catalyst has been well demonstrated by orderly characterization techniques, including bandgap measurement, Mott-Schottky plots, and Valance band spectra. The absence of other possible products such as H2 and less amount of CO suggests the selectivity and reaction pathway of the CO2 reduction process.
The proposed research is closely connected to two major alarming concerns of present times: global energy crisis and environmental pollution. Due to the high significance of this topic in our modern society, the impact of the proposed research on the scientific community as well as industry is going to be huge within Europe as well as throughout the world. As a result it is anticipated that the outcomes of research will attain good citation rates soon after publication. Benefitting from the new ideas of the PCO2R proposal will ensure establishing intellectual property rights through filing patents and copyrights or in some case treating the idea as a trade secret depending on the research outcomes. Consequently the importance and high quality of the proposed research will help me to establish as a world-class expert in the field of chemical engineering and materials science which is very crucial for my individual growth as an independent scientific researcher. The results of this project would be of immediate interest to the scientific community and industry, at a later stage it is bound to connect with the general public because of the long run impacts of CO2 reduction from atmosphere on global climate and environment.
The proposed research is closely connected to two major alarming concerns of present times: global energy crisis and environmental pollution. Due to the high significance of this topic in our modern society, the impact of the proposed research on the scientific community as well as industry is going to be huge within Europe as well as throughout the world. As a result it is anticipated that the outcomes of research will attain good citation rates soon after publication. Benefitting from the new ideas of the PCO2R proposal will ensure establishing intellectual property rights through filing patents and copyrights or in some case treating the idea as a trade secret depending on the research outcomes. Consequently the importance and high quality of the proposed research will help me to establish as a world-class expert in the field of chemical engineering and materials science which is very crucial for my individual growth as an independent scientific researcher. The results of this project would be of immediate interest to the scientific community and industry, at a later stage it is bound to connect with the general public because of the long run impacts of CO2 reduction from atmosphere on global climate and environment.