The generation of sustainable and stable semiconductors for solar energy conversion by photoredox catalysis, for example, light-induced water splitting and carbon dioxide reduction, is a key challenge of modern materials chemistry. Here we present a simple synthesis of a ternary semiconductor, boron carbon nitride, and show that it can catalyse hydrogen or oxygen evolution from water as well as carbon dioxide reduction under visible light illumination. The ternary B–C–N alloy features a delocalized two-dimensional electron system with sp2 carbon incorporated in the h-BN lattice where the bandgap can be adjusted by the amount of incorporated carbon to produce unique functions. Such sustainable photocatalysts made of lightweight elements facilitate the innovative construction of photoredox cascades to utilize solar energy for chemical conversion.

Ternary boron carbon nitride (BCN) semiconductors have been developed as emerging metal-free photocatalysts for visiblelight reduction of CO 2 , but the achieved efficiency is still not satisfying. Herein, we report that the CO 2 photoreduction performance of a bulk BCN semiconductor can be substantially improved by surface engineering with CdS nanoparticles. The CdS/BCN photocatalysts are characterized completely by diverse tests (e.g., XRD, FTIR, XPS, DRS, SEM, TEM, N 2 sorption, PL, and transient photocurrent spectroscopy). Performance of the CdS/BCN heterostructures is evaluated by reductive CO 2 conversion reactions with visible light under benign reaction conditions. Compared with bare BCN material, the optimized CdS/BCN photocatalyst exhibits a 10-fold-enhanced CO 2 reduction activity and high stability, delivering a considerable CO production rate of 12.5 μmol h −1 (250 μmol h −1 g −1 ) with triethanolamine (TEOA) as the reducing agent. The reinforced photocatalytic CO 2 reduction activity is mainly assigned to the obviously improved visible-light harvesting and the greatly accelerated separation/transport kinetics of light-triggered electron−hole pairs. Furthermore, a possible visible-light-induced CO 2 reduction mechanism is proposed on the basis of photocatalytic and photo(electro)chemical results.

The development of water oxidation catalysts (WOCs) to cooperate with light-energy transducers for solar energy conversion by water splitting and CO2 fixation is a demanding challenge. The key measure is to develop efficient and sustainable WOCs that can support a sustainable photocatalyst to reduce over-potentials and thus to enhance reaction rate of water oxidation reaction. Cobalt has been indentified as active component of WOCs for photo/electrochemical water oxidation, and its performance relies strongly on the contact and adhesion of the cobalt species with photoactive substrates. Here, cobalt is homogeneously engineered into the framework of pristine graphitic carbon nitride (g-C3 N4 ) via chemical interaction, establishing surface junctions on the polymeric photocatalyst for the water oxidation reaction. This modification promotes the surface kinetics of oxygen evolution reaction by the g-C3 N4 -based photocatalytic system made of inexpensive substances, and further optimizations in the optical and textural structure of Co-g-C3 N4 is envisaged by considering ample choice of modification schemes for carbon nitride materials.

We demonstrate here that two-dimensional boron nitride (h-BN) nanosheets can be employed as a robust supporting substrate to incorporate function metal oxides. The Cu2O@h-BN composites are thus obtained by dispersing Cu2O octahedrons on the surfaces of h-BN nanosheets. The -OH and -NH groups on the surfaces of h-BN nanosheets are found to be beneficial for anchoring Cu2O octahedrons. Moreover, the Cu2O@h-BN composites exhibit superior activity for the reduction of p-nitrophenol to pure Cu2O crystals and h-BN nanosheets. The h-BN component in the composites plays a critical role in the formation and adsorbing of the p-nitrophenolate ions, and, at the same time, Cu2O components react with brohydride ions and transfer a surface hydrogen species and electrons, resulting in the reduction of p-nitrophenol into p-aminophenol. Our results provide a new approach for the rational design and development of metal oxides composites and open the way to a range of important applications of h-BN-based materials.

Hexagonal boron nitride (h-BN) nanosheets, a promising layered material, have drawn more and more attention in recent years. In this study, a simple method has been developed to prepare stable colloidal h-BN nanosheet dispersion with high concentration in ethylene glycol based on the matching of the surface energies of h-BN and the surface tension of the solvent. It is found that bulk h-BN can be directly exfoliated and dispersed in ethylene glycol solvent with the assistance of sonication to form stable h-BN nanosheets with a few layers. Furthermore, the stable colloidal h-BN nanosheets have been demonstrated to be good carriers to support and disperse noble metal nanoparticles such as Ag, Au, and Pt with high catalytic activity for the reduction of p-nitrophenol. Our results suggest that stable colloidal h-BN dispersion with high concentration in ethylene glycol could open the way to a range of important applications of h-BN based materials.