Fine-tuning d-p hybridization in Ni-Bx cocatalyst for enhanced photocatalytic H2 production

The H 2 -evolution kinetics play a pivotal role in governing the photocatalytic hydrogen-evolution process. However, achieving precise regulation of the H-adsorption and H-desorption equilibrium (H ads /H des ) still remains a great challenge. Herein, we propose a fine-tuning d - p hybridization strategy to precisely optimize the H ads /H des kinetics in a Ni-B x modified CdS photocatalyst (Ni-B x /CdS). X-ray absorption fine-structure spectroscopy and theoretical calculations reveal that increasing B-atom amount in the Ni-B x cocatalyst gradually strengthens the d - p orbital interaction between Ni 3 d and B 2 p , resulting in a consecutive d -band broadening and controllable d -band center on Ni active sites. The above consecutive d -band optimization allows for precise modulation of the H ads /H des dynamics in the Ni-B x /CdS, ultimately demonstrating a remarkable H 2 -evolution activity of 13.4 mmol g -1 h -1 (AQE = 56.1 %). The femtosecond transient absorption spectroscopy further confirms the rapid electron-transfer dynamics in the Ni-B x /CdS photocatalyst. This work provides insights into the optimal design of prospective H 2 -evolution catalysts.