The photocatalytic activity of protonated ordered mesoporous carbon nitride (pom-CN) was significantly improved by assembling anionic [Mo3S13]2− clusters as cocatalysts onto the surface and channel of pom-CN via electrostatic interactions. This work demonstrates the feasibility of employing solution chemistry to assemble co-catalysts in the form of ionic clusters as building blocks into a photosynthetic architecture.

Porous hematite photoanodes with wormlike networks were prepared by microwave-assisted rapid annealing of β-FeOOH grown directly on a FTO glass. The enhanced electrochemical characteristics such as large surface area and good permeation of an electrolyte lead to the excellent photoelectrochemical performance toward the solar-driven water splitting for hydrogen production.

•A noble-metal-free photocatalytic system was developed by modifying mpg-CN with CoS using an impregnation-sulfidation approach.•CoS modified mpg-CN showed enhanced photocatalytic activity for H2 evolution under visible light.•CoS improved the kinetics of hydrogen production in the photocatalytic system.Mesoporous graphitic carbon nitride (mpg-CN) was modified with cobalt sulfide (CoS) by using an impregnation-sulfidation approach. The gas-phase sulfidation of CoS in nanoporous networks at certain temperature allows for the formation of intimate contact between the host carbon nitride and CoS nanoparticle, establishing noble-metal free heterojunctions for charge separation and collection at material interface. The resultant CoS/mpg-CN was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2-sorption, X-ray photoelectron spectroscopy (XPS), UV–Vis diffuse reflectance spectroscopy, photoluminescence (PL) spectroscopy and electrochemical measurement. On the basis of the physicochemical and electrocatalytic characterization results of CoS/mpg-CN, it was revealed that CoS functioned as a cocatalyst to promote the migration of excited electron from mpg-CN toward CoS as well as to provide reactive sites for H2 production at lower overpotentials. As a result, the rate of H2 evolution over mpg-CN under visible light illumination (λ > 420 nm) was significantly improved after loading with CoS and the optimal loading amount of CoS was found to be 1.0 at. %.

•MS/Si-NW photocathode was fabricated by coupling p-Si nanowires with MoS clusters.•MS/Si-NW exhibited an enhanced PEC performance for H2 production.•Nanotexturing is a feasible approach to obtain efficient photoelectrode.p-Si nanowire (Si-NW) arrays are successfully decorated with molybdenum–sulfur (MS) clusters by a drop-casting method. The composited photocathode (MS/Si-NW) demonstrated an enhanced photoelectrochemical (PEC) hydrogen production performance, with a photocurrent density of −14.3 mA/cm2 at a potential of 0 V vs. RHE under the illumination of the red part of simulated solar light (λ > 590 nm, 27.3 mW/cm2). The photocathode also showed a good stability in the long-term photocatalytic hydrogen evolution measurement, and the Faradaic efficiency of hydrogen production was close to 100%. Additionally, the morphological, optical and wetting properties of the photoelectrodes were investigated in detail. On the basis of the results, it could be concluded that the enhanced PEC performance is attributed to the high surface area, low light reflection and good wetting property of Si-NW, together with a low overpotential for hydrogen evolution reaction (HER) of the molybdenum–sulfur clusters.Efficient photoelectrochemical hydrogen evolution has been achieved over p-Si nanowire arrays decorated with molybdenum-sulfur clusters.

Porous hematite photoanodes with wormlike networks were prepared by microwave-assisted rapid annealing of β-FeOOH grown directly on a FTO glass. The enhanced electrochemical characteristics such as large surface area and good permeation of an electrolyte lead to the excellent photoelectrochemical performance toward the solar-driven water splitting for hydrogen production.