SP-carbon-mediated d‐band center for enhanced interfacial electric field promote photocatalytic hydrogen production

The hydrogen evolution kinetics plays a pivotal role in governing the photocatalytic hydrogen evolution process. However, achieving significant enhancement of photocatalytic hydrogen evolution kinetics through constructing heterojunctions to modulate the d-band center of transition metals remains a formidable challenge. Graphdiyne (GDY) has emerged as a rising star in the field of photocatalysis, owing to its distinctive sp-hybridized carbon triple bonds as catalytic active sites and extended π-conjugated structure. In this study, based on the successfully synthesized GDY, an organic-inorganic GDY/Ca 2 Co 2 O 5 S-scheme heterojunction was successfully constructed through a simple impregnation method, and the precise regulation of the d-band center was achieved, bringing it closer to the Fermi level. This regulation significantly affected the adsorption bonding stability and strength on the catalyst surface. Thereby effectively reducing the kinetic potential barrier of the hydrogen evolution reaction. Moreover, the Fermi energy level difference between GDY and Ca 2 Co 2 O 5 . leads to electron rearrangement at the interface, forming a strong internal electric field (IEF) at the S-scheme heterojunction interface and promoting the directional migration of photogenerated carriers. This study not only provides effective insights for the construction of organic-inorganic S-scheme heterojunctions, but also offers an important reference for optimizing the hydrogen evolution reaction kinetics through the rational regulation of the d-band center of transition metals by organic substances. • The organic-inorganic GDY/Ca 2 Co 2 O 5 S-scheme heterojunction was successfully constructed • Organic sp-C reasonably regulates the center of the transition metal d-band • There exists an intrinsic electric field between GDY and Ca 2 Co 2 O 5 • The electronic state density has increased significantly • The synergistic effect of d-band center optimization and S-scheme heterojunctions