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Electrochemical conversion of carbon dioxide (CO 2 ) to chemicals or fuels can effectively promote carbon capture and utilization, and reduce greenhouse gas emission but a serious impediment to the process is to find highly active electrocatalysts that can selectively produce desired products. Herein, we have established the design principles based on the density functional theory calculations to screen the most promising catalysts from the family of coordinately unsaturated/saturated transition metal (TM) embedded into covalent organic frameworks (TM-COFs). An intrinsic descriptor has been discovered to correlate the molecular structures of the active centers with both the activity and selectivity of the catalysts. Among all the catalysts, the coordinately unsaturated Ni-doped covalent triazine framework (Ni-CTF) is identified as one of the best electrocatalysts with the lowest overpotential (0.34 V) for CO 2 reduction toward CO while inhibiting the formation of the side products, H 2 and formic acid. Compared with coordinately saturated TM-COFs and noble metals ( e.g. Au and Ag), TM-CTFs exhibit higher catalytic activity and stronger inhibition of side products. The predictions are supported by previous experimental results. This study provides an effective strategy and predictive tool for developing desired catalysts with high activity and selectivity. 

Abstract Carbon nanomaterials are promising metal‐free catalysts for energy conversion and storage, but the catalysts are usually developed via traditional trial‐and‐error methods. To rationally design and accelerate the search for the highly efficient catalysts, it is necessary to establish design principles for the carbon‐based catalysts. Here, theoretical analysis and material design of metal‐free carbon nanomaterials as efficient photo‐/electrocatalysts to facilitate the critical chemical reactions in clean and sustainable energy technologies are reviewed. These reactions include the oxygen reduction reaction in fuel cells, the oxygen evolution reaction in metal–air batteries, the iodine reduction reaction in dye‐sensitized solar cells, the hydrogen evolution reaction in water splitting, and the carbon dioxide reduction in artificial photosynthesis. Basic catalytic principles, computationally guided design approaches and intrinsic descriptors, catalytic material design strategies, and future directions are discussed for the rational design and synthesis of highly efficient carbon‐based catalysts for clean energy technologies.