Chong Qing Huang, Carlos A. Triana, Bingquan Jia, Nanchen Dongfang, Rolf Erni, Daniel F. Abbott, Robin N. Dürr, Han Zhao, Victor Mougel, Marcella Iannuzzi, Greta R. Patzke
The oxygen evolution reaction (OER) is a vital bottleneck for the conversion of water and clean energy into chemical fuels through electrocatalysis. In-depth insights into the surface structural evolution of real active species on catalysts during the OER process are of great significance for knowledge-driven catalyst design. Herein, we developed iron-doped cobalt carbodiimide (Co x Fe 1– x NCN) nanoparticles as efficient OER precatalysts with stable overpotential for at least 290 h. Advanced structural characterizations disclosed the presence of abundant structural defects in low-crystalline (LC) Co x Fe 1– x NCN. Operando X-ray absorption spectroscopy and X-ray diffraction studies revealed that these intrinsic structural defects could accelerate the irreversible surface reconstruction in LC-Co x Fe 1– x NCN. This promoted the generation of high-valent metal oxyhydroxides as the real active OER phases, resulting in a lower overpotential compared to high-crystalline Co x Fe 1– x NCN. The present study highlights the introduction of structural defects as an effective approach for the rational design of efficient OER electrocatalysts.