In situ synthesis of Cu3P/g-C3N4 heterojunction with superior photocatalytic hydrogen evolution

Abstract

The low-cost and high-efficient Cu3P/g-C3N4 photocatalyst was prepared through one-step in situ solvothermal approach. The characterization results proved that Cu3P nanoparticles with high purity and good crystallinity were uniformly embedded on the g-C3N4 nanosheets. The maximal H2 evolution rate can be enhanced to 4909.9 mol · g−1 · h−1, which is 71.1 times higher than bare g-C3N4. The markedly photocatalytic H2 production was mainly because of increased active sites and the intimate contact interfaces by in situ growth of Cu3P nanoparticles on g-C3N4 nanosheets, which greatly boost the separation and transport of photo-induced electro-hole pairs. The enhanced mechanism was proposed and verified by the photoluminescence spectra, transient photocurrent responses and electrochemical impedance spectroscopy results. This one-step solvothermal synthesis paves a new way for in situ construction of highly efficient transition metal phosphides/carbon nitride photocatalyst and application of photocatalytic splitting water system.Highlights• Fabricated Cu3P/g-C3N4 heterojunction by one-step in situ solvothermal approach.• The optimized H2 evolution rate is 4909.9 µmol · g−1 · h−1 for 3 wt% Cu3P/g-C3N4.• The quantum efficiency (QE) is 22.1% (under 300W Xe lamp with 400 ± 7.5 nm band-pass filter).• Photocatalytic enhancement mechanism of Cu3P/g-C3N4 composite was proposed.