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The development of economical multiphase photocatalysts is a significant challenge in achieving large-scale industrialization. Rational catalyst design can help in achieving efficient, energy-saving, and green catalytic reactions, making it more feasible to screen potential catalyst candidates. In this paper, we have successfully developed a high-efficiency photocatalyst Cu-doped Cu2WO4(OH)2(CWOH-y, where y represents the molar ratio of copper tungsten source), which can catalyze the aerobic coupling reaction of amines to produce corresponding imines under visible light irradiation. N-benzylidenebenzylamine is synthesized under visible light at 25 °C with an 89 % yield. Under natural light at around 35 °C (mean light intensity of 50 mW/cm2), 94 % of the benzylamine is converted, and 97 % of the product is N-benzylidenebenzylamine. The catalyst exhibits high efficiency due to the synergistic effect of doped Cu, Cu2WO4(OH)2, and visible light. This combination generates a significant amount of superoxide free radicals and singlet oxygen when exposed to visible light. Furthermore, the catalyst demonstrates universality and stability with a wide range of amine derivatives. This study introduces a new environmentally friendly photocatalytic pathway for the synthesis of imines and emphasizes the potential applications of Cu2WO4(OH)2.

KTi3NbO9nanoparticles were fabricated viaa simple hydrothermal method with a post-calcination treatment. The nitrogen doping (N-KTi3NbO9) leads to a narrow band gap, which in turn facilitates efficiently catalysis of imine deamination under purple light that matches its absorption spectra. Furthermore, N-KTi3NbO9exhibits excellent performance in the tandem reaction of photocatalytic imine formation and deamination from various amines. The conversion of benzylamine was up to 100% with >85% benzaldehyde selectivity.

Ru/TiO2catalysts exhibit excellent catalytic performance for selective reduction of 4-nitroacetophenone to 4-aminoacetophenone at normal temperature and atmospheric hydrogen pressure. Moreover, 99.9% selectivity to 4-aminoacetophenone can be obtained over 2.7 wt% Ru/TiO2(anatase) catalyst even in a relatively wide temperature (55–115 °C) and time (1–12 h) range. Its excellent catalytic performance is derived from the activation of H2on the Ru nanoparticles at atmospheric pressure and the strong interaction of nitro groups with the support surface. Additionally, Ru nanoparticles supported on different crystalline TiO2phases (anatase and rutile) result in different reaction pathways for 4-nitroacetophenone. Since the Ti–Ti distance on the rutile surface is smaller than that on the anatase surface, the hydroxylamine species adsorbed on the Ti atoms of rutile are more susceptible to the coupling reaction. Therefore, Ru/TiO2(rutile) causes a series of intermediates to accumulate during the conversion process, while Ru/TiO2(anatase) allows the highly selective conversion of 4-nitroacetophenone to 4-aminophenone. In addition, Ru/TiO2(anatase) can achieve chemoselective reduction of nitroaromatics to the corresponding anilines in the presence of –CN, –CHO, and –COOH, especially nitroaromatics containing CC and CC, indicating the excellent applicability.

Reducing high overpotential for the oxygen evolution reaction (OER) is an important challenge for the utilization of clean and renewable energy resources. An obstacle that badly impedes the design of efficient OER catalysts is the weak understanding of the oxygen intermediates. Because of the aqueous reaction environment of OER, direct detection of oxygen intermediates is very challenging. Herein, we develop a general method for operando probing OER intermediates under real working conditions. We proved that the electrochemically generated oxygen intermediates of OER, e.g., OH*, are electrophiles, which could be probed by reaction with nucleophiles such as alcohol molecules. The exceptional generality of this method is demonstrated in different reaction mediums (alkaline and acid) and on various types of materials (oxides and hydroxides). The new insights of the surface chemistry on OER catalysts from the experimental approach will benefit the design of new catalysts to reduce the cost of hydrogen production.

A high aniline yield was achieved by the combination of near-UV light as the driving force of nitrobenzene reduction and a ZnNb2O6surface as the product-selective controller. Here, a ZnNb2O6fibre, having a wide band gap and both acidic and basic sites, was exploited by a novel ion-exchange method to study the effect of the surface acidity and basicity of catalysts on the product selectivity under near-UV light irradiation without the interference of photo-generated carriers. ZnNb2O6showed the highest aniline yield compared to Nb2O5and ZnO. The results of experimental and theoretical calculations confirmed that the acidic sites on the surface of ZnNb2O6promoted the breakage of the N–O bond in the intermediate phenylhydroxylamine while the basic sites were attached to the dissociated hydrogen of isopropyl alcohol, resulting in high aniline selectivity.

HCl-Doped polyaniline (PANI-ES) and PANIs of different oxidation states were prepared by a typical oxidative polymerization and subsequent redox reaction, respectively. The photocatalytic performance of PANIs towards selective benzylamine oxidation reactions under visible light was investigated. PANI-ES containing a polaron structure exhibited the highest light-induced activity (54.9%). The results show that the formation of the surface complex between PANI-ES and adsorbed amine should be responsible for the enhanced visible light activity. The newly formed polaron band in PANI-ES has a greater number of delocalized electrons, which can facilitate electron transfer and thus improve the photoactivity. These results indicate that conjugated conducting polymers can be efficient visible light-responsive nonmetal photocatalysts for green synthesis.

To improve the photocatalytic performance of TiO2and make it easier to recycle, the titanosilicate@anatase core-shell micro-nanostructure photocatalysts were designed. The titanosilicate@anatase core-shell micro-nanostructure was fabricated by a two-step method: an acid-assisted hydrothermal treatment of the hydrogen-form natisite and a subsequent calcination. In the first step, the dissolution and recrystallization of Ti species led to the formation of TiO2shell over the titanosilicate; in the second step, the calcination not only facilitated the formation of Ti−O−Si bond, but also improved the crystallization of TiO2shell. The rutile TiO2was not detected even at 900 °C, which could be attributed to the strong interaction between TiO2nanocrystals and the titanosilicate core through Ti−O−Si bond at the interface. The formation of Ti−O−Si bond also changed the surface characteristic of the TiO2shell, which facilitated the enrichment of RhB dye molecules around the catalyst and induced the fast production of the O2•−. The collaboration of the core and the shell contributed to the quick degradation of RhB under visible light and the excellent recycling performance. The growth kinetics of the core-shell micro-nanostructure has been studied in detail, which provided a novel and facile synthesis strategy for the fabrication of TiO2micro-nanostructure easy to be recycled.