Zhou Yi, Wang Yaqi, Chen Shuo, Yu Hongtao, Su Yan, Quan Xie
Key Laboratory of Industrial Ecology and Environment Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, PR China.
Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Ministry of Education, School of Physics, Dalian University of Technology, Dalian 116024, China.
ACS Appl Mater Interfaces. 2025 Jan 8;17(1):969-979. doi: 10.1021/acsami.4c16101. Epub 2024 Dec 29.
Photocatalytic conversion of carbon dioxide (CO) to fuel provides an ideal pathway to achieving carbon neutrality. One significant hindrance in achieving the reduction of CO to higher energy density multicarbon products (C) was the difficulty in coupling C-C bonds efficiently. Copper (Cu) is considered the most suitable metal catalyst for C-C coupling to form C products in the CO reduction reaction (CORR), but it encounters challenges such as low product selectivity and slow catalytic efficiency. Herein, we constructed a carbon defect on Cu-doped carbon nitride (Cu-CN), as an efficient catalyst for photocatalytic CORR. The optimized catalyst (Cu-CN-550) with a carbon defect shows high photocatalytic activity for CO reduction to ethanol, with an ethanol production rate of 122.6 μmol g h and a selectivity of 93.7%. The yield was 4.5 times higher than that of the Cu-CN-550 without carbon defect. The ratio of Cu/Cu in Cu species changes regularly with calcination temperature, which was linearly correlated with the selectivity of the liquid product of CORR. DFT calculations combined with experimental results revealed that Cu doping promoted CO activation, followed by enhanced *CO adsorption and weakened hydrogenation and desorption. Carbon defects lower the free energy and greatly accelerate the *CO transfer process by promoting the formation of a six-membered ring intermediate state, serving as an intramolecular catalyst for *CO dimerization. Synergistic thermodynamic and kinetic interactions were realized through Cu doping and the introduction of carbon defects, thereby enhancing the catalytic performance of photocatalytic reduction of CO for ethanol production.
将二氧化碳（CO₂）光催化转化为燃料为实现碳中和提供了一条理想途径。在将CO₂还原为更高能量密度的多碳产物（C₂+）方面，一个重大障碍是难以有效地耦合C-C键。铜（Cu）被认为是在CO₂还原反应（CORR）中用于C-C耦合以形成C₂+产物的最合适金属催化剂，但它面临着诸如产物选择性低和催化效率慢等挑战。在此，我们在掺铜氮化碳（Cu-CN）上构建了一个碳缺陷，作为光催化CORR的高效催化剂。具有碳缺陷的优化催化剂（Cu-CN-550）对将CO₂还原为乙醇表现出高光催化活性，乙醇产率为122.6 μmol g⁻¹ h⁻¹，选择性为93.7%。该产率比没有碳缺陷的Cu-CN-550高4.5倍。Cu物种中Cu⁺/Cu²⁺的比例随煅烧温度有规律地变化，这与CORR液体产物的选择性呈线性相关。密度泛函理论（DFT）计算结合实验结果表明，Cu掺杂促进了CO₂的活化，随后增强了CO的吸附并削弱了氢化和解吸。碳缺陷降低了自由能，并通过促进六元环中间态的形成极大地加速了CO的转移过程，作为*CO二聚化的分子内催化剂。通过Cu掺杂和引入碳缺陷实现了协同的热力学和动力学相互作用，从而提高了光催化还原CO₂制乙醇的催化性能。
