One-Step Strategy to Maximize Single-Atom Catalyst Utilization in Nitrate Reduction via Bidirectional Optimization of Mass Transfer and Electron Supply
Xianhu Long, Fan Huang, Tao P. Zhong, Huinan Zhao, Ping Li, Jingyun Fang, Shuanghong Tian, Dong Shu, Chun He
Abstract
Single-atom catalysts offer exceptional performance but face practical challenges due to complex synthesis and low efficiency caused by mass transfer resistance. In this study, based on a simple one-step pyrolysis method, we designed a Cu single-atom catalyst with high active site exposure and a locally electron-deficient environment (HE Cu 1 –N 4 ) to achieve maximum utilization efficiency in electrocatalytic nitrate reduction (NO 3 RR). Using advanced characterization techniques, we confirmed that its unique 3D structure enhances Cu atom exposure and reduces nitrate (NO 3 – ) mass transfer resistance. Synchrotron radiation and DFT calculations showed that adjusting the coordination environment induces a local electron-deficient effect in Cu atoms, increasing the electrostatic attraction to NO 3 – . HE Cu 1 –N 4 achieved 100% NH 3 selectivity across a wide range of NO 3 – concentrations, with an NH 3 yield (5.09 mg h –1 mg cat –1 ) nearly 7-fold higher than that of the conventional unmodified Cu single-atom catalyst (Cu 1 –N 2, 0.73 mg h –1 mg cat –1 ). Under pilot-scale conditions, HE Cu 1 –N 4 demonstrated strong resistance to interference and excellent stability in complex water systems. A simple modification method enhanced the utilization efficiency of single atoms in single-atom catalysts, significantly improving the catalytic activity of the material. Moreover, this straightforward synthesis strategy holds promise for the large-scale production of single-atom catalysts, paving the way for practical engineering applications.