Copper is a low-cost plasmonic metal. Efficient photocatalysts of copper nanoparticles on graphene support are successfully developed for controllably catalyzing the coupling reactions of aromatic nitro compounds to the corresponding azoxy or azo compounds under visible-light irradiation. The coupling of nitrobenzene produces azoxybenzene with a yield of 90 % at 60 °C, but azobenzene with a yield of 96 % at 90 °C. When irradiated with natural sunlight (mean light intensity of 0.044 W cm(-2) ) at about 35 °C, 70 % of the nitrobenzene is converted and 57 % of the product is azobenzene. The electrons of the copper nanoparticles gain the energy of the incident light through a localized surface plasmon resonance effect and photoexcitation of the bound electrons. The excited energetic electrons at the surface of the copper nanoparticles facilitate the cleavage of the NO bonds in the aromatic nitro compounds. Hence, the catalyzed coupling reaction can proceed under light irradiation and moderate conditions. This study provides a green photocatalytic route for the production of azo compounds and highlights a potential application for graphene.

Highly selective hydrogenation of cinnamaldehyde to cinnamyl alcohol with 2-propanol was achieved using SiC-supported Au nanoparticles as photocatalyst. The hydrogenation reached a turnover frequency as high as 487 h(-1) with 100% selectivity for the production of alcohol under visible light irradiation at 20 °C. This high performance is attributed to a synergistic effect of localized surface plasmon resonance of Au NPs and charge transfer across the SiC/Au interface. The charged metal surface facilitates the oxidation of 2-propanol to form acetone, while the electron and steric effects at the interface favor the preferred end-adsorption of α,β-unsaturated aldehydes for their selective conversion to unsaturated alcohols. We show that this Au/SiC photocatalyst is capable of hydrogenating a large variety of α,β-unsaturated aldehydes to their corresponding unsaturated alcohols with high conversion and selectivity.

This paper presents a carbon nanocoil supported Pd nanoparticle system (Pd/CNCs) as a photocatalyst for coupling reaction of aryl halides and alkenes (Heck reaction) at 40 °C.

Carbon dots modified with polydopamine (CDs/PDA), a low‐cost and environmentally friendly photothermal material, is prepared in this work. The results show that the polymerization of dopamine is significantly accelerated due to the interaction between CDs and dopamine. Importantly, the interaction also greatly promotes nonradiative recombination of photoexcited charge carriers, thereby enhancing the photothermal conversion performance of CDs/PDA. The obtained CDs/PDA composite shows superior photothermal evaporation efficiency in comparison with CDs and PDA owing to the enhanced light absorption, porous structure, and appropriate interaction. In addition, CDs/PDA exhibits excellent stability. These merits enable CDs/PDA show great promise in solar‐energy‐related applications.