Modulating local coordination structure over single Pt atom to optimize adsorption behavior for high-efficiency photocatalytic H₂ production

The development of single-atom photocatalysts featuring precisely defined coordination structure is of great significance for elucidating the correlations between catalytic performances and coordination structures, yet it remains a grand challenge. Herein, the asymmetric/symmetric Pt-N_x moieties in carbon nitride (denoted as Pt-N_x@MCT, x equals to a coordination number of 3 or 4) are elaborately constructed by a coordination structure regulation strategy. The hydrogen production performances of Pt-N₃@MCT and Pt-N₄@MCT photocatalysts display a relationship with the Pt-N coordination numbers, with Pt-N₃@MCT showing a photocatalytic activity (195 μmol h⁻¹) 3 times that of Pt-N₄@MCT (65 μmol h⁻¹) and an apparent quantum yield of 34.1 % at 420 nm. The asymmetric Pt-N₃ moiety in Pt-N₃@MCT acts as electron collector to promote the separation and transfer of charge carriers and to create the higher occupied Pt d orbital, weakening the bond strength between hydrogen intermediates and Pt atomic sites and accelerating hydrogen production reaction kinetics in Pt-N₃@MCT.