Synergistic dual doping and directed structural engineering of 2D cobalt tellurium nanoarchitectures for practical-level overall water splitting

Developing low-cost and durable bifunctional electrocatalysts for overall water splitting is crucial for scalable green hydrogen production. Herein, we report a dual-cation-doped Ru,Mn-CoTe₂ catalyst with a porous nanosheet architecture, synthesized via a Mo-assisted route followed by in situ tellurization and controlled Ru incorporation. The inclusion of Mo during precursor formation directs the evolution of a sheet-like CoMnMo-LDH, while its removal during tellurization generates abundant pores and defect sites favorable for Ru anchoring. The advances in synergistic dual doping and directed structural engineering are evidenced by DFT calculations, which confirm an optimized hydrogen adsorption energy (ΔG_H* = -0.081 eV) for HER and a low OER overpotential of 0.54 V. The Ru,Mn-CoTe₂ exhibits outstanding bifunctional activity, requiring only 39 mV for HER and 220 mV for OER to reach 10 mA cm^-2 in 1.0 M KOH. An electrolyzer cell also demonstrates an exceptional cell voltage of 1.69 V to achieve a current density of 0.5 A cm^-2 in 1.0 M KOH at 60 °C, along with prospective stability, sustaining 600 h of continuous operation. This work establishes a rational dual-doping and structural-engineering strategy for designing highly active, stable, and scalable telluride-based catalysts for industrial water electrolysis and sustainable hydrogen generation.