Unprecedented Hydrogen Evolution Reactions Based on the Accelerating Effect of [Co-Tb]-Supramolecular Complex-Anchored CdS Heterojunctions

This study presents a series of 1-Tb/CdS binary heterojunctions, synthesized by combining 1-Tb (a Co³⁺-Tb³⁺-based supramolecular complex) and CdS in various weight ratios via a solvothermal process. These heterojunctions have been thoroughly characterized to elucidate their chemical, structural, and optoelectronic properties. The catalytic effectiveness of these heterojunctions was evaluated with respect to the hydrogen evolution reaction (HER), spanning photocatalytic, electrocatalytic, and photoelectrocatalytic processes. Significantly outperforming individual photocatalysts (CdS and 1-Tb) and other binary heterostructures, the 7.5-1-Tb/CdS heterojunction exhibited the highest catalytic HER efficiency. The exceptional catalytic performance of 7.5-1-Tb/CdS is attributed to a synergistic integration of 1-Tb and CdS, enabling a highly efficient Z-scheme heterojunction. This unique architecture enhances charge separation and transfer by leveraging the complementary electronic properties of the individual CdS and 1-Tb semiconductors while minimizing recombination losses. X-ray photoelectron spectroscopy, band structure analysis, photoluminescence, and electrochemical impedance spectroscopy further validated the Z-scheme mechanism, highlighting the optimal alignment of energy levels. Overall, this study highlights the potential of 1-Tb/CdS binary heterojunctions as robust and efficient catalysts for the HER. The simplicity of the synthesis process, coupled with the exceptional catalytic activity, offers a significant advancement in clean energy technologies, paving the way for sustainable hydrogen production.