@article{Yang2026, 
author = {Jielian Yang and Bing Chen and Yue Shen and Qi Wu and Yuemei Liao and Jin Guo and Naixin Lyu and Liya Zhou and Peican Chen and Anxiang Guan and Zaiwang Zhao},
title = {Built-in electric field-regulated *H-catalyst distance enables efficient CO2-to-CH4 electroreduction},
year = {2026},
journal = {Nano Research},
keywords = {built-in electric field, *H–catalyst distance, H-near configuration, CO2-to-CH4 conversion},
url = {https://www.sciopen.com/article/10.26599/NR.2026.94908984},
doi = {10.26599/NR.2026.94908984},
abstract = {Electrochemical CO2 reduction reaction (CO2RR) to CH4 represents a promising pathway toward carbon neutrality, yet it is severely limited by sluggish multi-electron/proton transfer kinetics, low selectivity, and insufficient proton supply. Herein, we rationally fabricate a series of Cu-doped Er2O3 catalysts (Cu-Er2O3-x) via sequential precipitation and calcination, which engineer a strong built-in electric field (BIEF) for efficient and selective CO2-to-CH4 conversion. Cu doping triggers significant charge redistribution between Cu and Er2O3, forming positively charged Cu sites and a negatively polarized Er2O3 matrix. The generated BIEF reorients interfacial water into an H-near configuration, shortens the *H-catalyst distance, promotes water dissociation, and optimizes *CHO adsorption. The optimal Cu-Er2O3-6 catalyst achieves a high CH4 Faradaic efficiency of 60.79% and a large CH4 partial current density of −28.01 mA cm–2 at −1.6 V vs. RHE in an H-type cell, with outstanding 24 h stability. In situ ATR-SEIRAS, electrochemical tests, and DFT calculations reveal that BIEF-modulated water orientation and electronic optimization accelerate proton transfer and lower the energy barrier of the rate-determining *CHO→*CH2O step. This work provides a robust strategy for boosting CO2RR performance via BIEF engineering and *H–catalyst distance regulation, offering a valuable design principle for advanced CH4-selective electrocatalysts.}
}