Rational design of interfacial energy level matching for CuGaS2 based photocatalysts over hydrogen evolution reaction

CuGaS 2 (CGS) is effectively synthesized by a one-step solid-phase sintering method. The conduction band maximum, valence band maximum and flat band potential of the obtained CGS are −1.14, 1.21 and 0.33 V vs RHE, respectively. When the Cu to Ga atom ratio is 1: 1.4 in the raw material, the prepared CuGaS 2 exhibits the highest visible-light (λ˃420 nm) H 2 production activity. The hydrogen production rate of CuGaS 2 reaches 1.12 mmol g −1 h −1 under visible-light radiation. When Ruthenium is loaded as cocatalyst, the H 2 production rate of CuGaS 2 @Ru is promoted to 3.38 mmol g −1 h −1 . At the same, the interior component of photo-induced carries transfer among photoharvestor and cocatalyst has been revealed. This research provides a facile strategy to fabricate CuGaS 2 with excellent photocatalytic performance for H 2 production. • CuGaS 2 visible-light photocatalyst was synthesized by a facile method. • The bandgap of the CuGaS 2 semiconductor is 2.35 eV. • The visible-light HER rate of CuGaS 2 @Ru reaches 3.38 mmol g −1 h −1 . • The interface mechanism of CuGaS 2 @Ru has been revealed.