Efficient photocatalytic hydrogen evolution by engineering amino groups into ultrathin 2D graphitic carbon nitride

[Display omitted] •Ultrathin 2D and –NH2 increase redox capability and charge kinetics.•Strong redox capability and charge kinetics boost photocatalytic performance.•2D CN-NH2 shows a high apparent quantum efficiency (~13.4%) at λ = 420 nm. Increased energy demands coupled with the environmental crisis have encouraged extensive research on renewable energy resources to generate H2 fuel. The photocatalytic water splitting reaction which directly converts solar energy into H2 is an appreciated alternative, among which, the thermodynamic constraint and slow reaction kinetics are critical factors for developing efficient semiconductor-based photocatalysts. Here, we report an amino group (–NH2) functionalized ultrathin two-dimensional (2D) graphitic carbon nitride (2D CN-NH2) with strong redox capability and accelerated photocatalytic reaction kinetics. Specifically, the ultrathin 2D structure improves the transfer and separation efficiency of the photogenerated charge carriers and increases the band gap of 2D CN-NH2. –NH2 functions as a photogenerated hole stabilizer, which can prolong the lifetime of photogenerated charge carriers. Additionally, the Lewis basicity supplied by –NH2 can further boost the photocatalytic performance of 2D CN-NH2. The apparent quantum yield of the obtained 2D CN-NH2 reaches ~13.4% at 420 nm.