Visible-Light Photocatalytic Overall Water Splitting on a B 4 C 3 /C x N y Z-Scheme Heterojunction: Role of Ultrafast Carrier Recombination-Transfer Kinetics.

Herein, combining density functional theory (DFT) calculations with nonadiabatic molecular dynamics (NAMD), we built a computational framework to rationally screen from a series of 2D conjugated carbon nitrides (CNs) to match with B 4 C 3 , resulting in the excellent direct Z-scheme photocatalyst (B 4 C 3 /C 6 N 6 ) for overall water splitting (OWS). Studies on interface engineering and ultrafast dynamics of carrier recombination-transfer show that in the B 4 C 3 /C 6 N 6 system, compared with the slower interlayer migration process of carriers, strong nonadiabatic coupling and longer quantum decoherence time accelerates weak carrier interlayer recombination on a subpicosecond time scale, enabling simultaneous triggering of hydrogen evolution reaction (HER) with Δ G = -0.23 eV and spontaneous oxygen evolution reaction (OER) in the absence of sacrificial or cocatalysts. In general, our work will promote the design of efficient direct Z-scheme photocatalysts from an ultrafast dynamics perspective.