Two-dimensional (2D) transition-metal (groups IV, V, VI) carbides (MXenes) with formulas M₃C₂ have been investigated as CO₂ conversion catalysts with well-resolved density functional theory calculations. While MXenes from the group IV to VI series have demonstrated an active behavior for the capture of CO₂, the Cr₃C₂ and Mo₃C₂ MXenes exhibit the most promising CO₂ to CH₄ selective conversion capabilities. Our results predicted the formation of OCHO^• and HOCO^• radical species in the early hydrogenation steps through spontaneous reactions. This provides atomic level insights into the computer-aided screening for high-performance catalysts and the understanding of electrochemical mechanisms for CO₂ reduction to energy-rich hydrocarbon fuels, which is of fundamental significance to elucidate the elementary steps for CO₂ fixation.

中文翻译：

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了解过渡金属碳化物（MXenes）中CO ₂捕集并转化为碳氢化合物燃料的电化学机理

分子式为M ₃ C ₂的二维（2D）过渡金属（IV，V，VI族）碳化物（MXenes）已作为CO ₂转化催化剂进行了研究，具有很好的密度泛函理论计算能力。虽然IV至VI系列的MXene已表现出捕获CO ₂的活跃行为，但Cr ₃ C ₂和Mo ₃ C ₂ MXene表现出最有前途的CO ₂至CH ₄选择性转化能力。我们的结果预测了OCHO ^•和HOCO ^•的形成早期氢化中的自由基种类通过自发反应进行。这为计算机辅助筛选高性能催化剂提供了原子级的见解，并为将CO ₂还原为富能烃燃料提供了电化学机理的理解，这对于阐明CO ₂固定的基本步骤具有根本意义。