Manganese-doped amorphous core-shell cobaltous sulfide for enhanced photocatalytic hydrogen evolution

Rational modulation of co-catalyst properties through strategic metal doping and structural engineering emerges a promising approach to simultaneously tackle critical challenges in photocatalytic hydrogen evolution—specifically, suppressing photogenerated carrier recombination and optimizing hydrogen adsorption thermodynamics. This work demonstrates the synergistic integration of manganese doping and amorphous core-shell architecture in a bimetallic sulfide co-catalyst (Mn-CoS_x), designed to overcome the inherent limitations of conventional crystalline CoS systems. The developed Mn-CoS_x features a homogeneous nanostructure with an enlarged specific surface area (SSA ≈ 112.46 m² g⁻¹) and abundant exposed sulfur active sites, while Mn incorporation effectively reduces the hydrogen adsorption free energy (ΔG_H∗ = −0.51 eV) through d-band electronic structure modulation. When coupled with CdS photocatalysts, the optimized Mn-CoS_x/CdS composite achieves exceptional hydrogen evolution rates of 19.1 mmol g⁻¹ h⁻¹ under visible light irradiation, representing 9-fold enhancement over benchmark CoS/CdS, 112-fold over bare CdS, and 21-fold over Pt/CdS systems, respectively. Notably, the amorphous core-shell configuration not only facilitates efficient charge separation but also enables dynamic surface reconstruction during catalytic operation. This work establishes a universal design principle for transition metal-based co-catalysts through the synergistic combination of atomic-level doping strategies and nanoscale structural engineering, providing new insights into the development of cost-effective, noble metal-free photocatalytic systems for sustainable energy conversion.