Directional Charge Pumping from Photoactive P‐doped CdS to Catalytic Active Ni2P via Funneled Bandgap and Bridged Interface for Greatly Enhanced Photocatalytic H2 Evolution

Loading cocatalysts onto semiconductors is one of the most popular strategies to inhibit charge recombination, but the efficiency is generally hindered by the localized built‐in electric field and the weakly connected interface. Here, this work designs and synthesizes a 1D P‐doped CdS nanowire/Ni2P heterojunction with gradient doped P to address the challenges. In the composite, the gradient P doping not only creates a funneled bandgap structure with a built‐in electric field oriented from the bulk of P‐CdS to the surface, but also facilitates the formation of a tightly connected interface using the co‐shared P element. Consequently, the photogenerated charge carriers are enabled to be pumped from inside to surface of the P‐CdS and then smoothly across the interface to the Ni2P. The as‐obtained P‐CdS/Ni2P displays high visible‐light‐driven H2 evolution rate of ≈8265 µmol g−1 h−1, which is 336 times and 120 times as that of CdS and P‐CdS, respectively. This work is anticipated to inspire more research attention for designing new gradient‐doped semiconductor/cocatalyst heterojunction photocatalysts with bridged interface for efficient solar energy conversion. P‐CdS/Ni2P heterojunction composites with gradiently surface doped P are fabricated via a one‐step phosphorization method. The heterojunction establishes an efficient charge transfer channel that enables the photogenerated charge carriers to be pumped from inside to surface of the P‐CdS and then smoothly across the interface to the Ni2P, thereby enhancing the photocatalytic H2 evolution activity by two orders of magnitude.