Microwave-induced growth of {101̅0} faceted zinc oxide/graphene 2D/2D nanostructures for visible-light photocatalysis and hydrogen evolution reaction

The future hydrogen economy urges to replace platinum-based catalysts since large-scale production of hydrogen using platinum is not economically viable to deal with the influx of interest. Developing cost-effective, durable, and efficient catalysts is one of the most relevant research frontiers. Herein, interconnected and {101̅0} faceted 2D zinc oxide decorated on graphene sheets was effectively fabricated by a simple CTAB-assisted microwave technique and has been intensively investigated for photocatalytic dye degradation and electrocatalytic hydrogen evolution. The XRD and Raman spectra confirm the in-situ reduction of GO to rGO and successful synthesis of ZnO/rGO hybrids. Compared with the pure ZnO, as-obtained ZnO/rGO hybrids exhibited good stability and superior photocatalytic efficiency under visible-light irradiation, owing to reduced electron-hole pair recombination upon GO incorporation, as affirmed by PL spectra, TRPL lifetime measurements, and photocurrent responses. The 2D/2D ZnO/rGO hybrid nanostructure showed optimised material properties for exceptional electrochemical H2 evolution, producing a current density of − 10 mA/cm2 at a significantly reduced overpotential of − 810 mV vs. RHE, and a Tafel slope of 157 mV/dec in 0.5 M H2SO4. The enhanced catalytic activity can be attributed to the introduction of rGO sheets, which improved the surface area and electrical conductivity of the sample. The multifunctional nature of ZnO/rGO hybrids in both photocatalysis and electrocatalysis sheds light upon environmental pollution and the energy crisis.