The present work provides a critical review of the science and technological state-of-the-art of defect engineering applied to oxide perovskites in thermocatalytic, electrocatalytic, photocatalytic, and energy-storage applications.

water splitting techniques, however, large energy consumption in AWE and the use of noble-metal based catalysts in PEM electrolyzers prohibited the wide application of these water electrolysis techniques. Anion exchange membrane (AEM) water electrolyzer combines the merits of AWE and PEM electrolyzers, and is regarded as a promising future water electrolysis technology with notable advantages, including the simple and compact structure and the use of earth-abundant transition metal catalysts. [2,3] However, the development of the AEM electrolyzer is still in its infancy to date. Developing high-efficient and stable electrocatalysts is highly required to improve the current density and energy efficiency of the AEM water electrolyzer.Between the two half-cell reactions in the AEM water electrolyzer, hydrogen evolution reaction (HER) is more challenging in alkaline media due to its sluggish kinetics. The additional water dissociation step to generate proton (H*) sources results in 2-3 orders of lower activity than that in the PEM electrolyzer. [4] Various transition metal (TM)based materials have been developed in recent years to improve HER activity in alkaline media, including TM sulfides, [5,6] selenides, [7,8] and phosphides. [9][10][11][12] In particular, nickel phosphides have attracted great attention due to their high electronic conductivity and structural diversity. However, pure-phase metal phosphides have relatively large absolute values of Gibbs free Regulating the electronic structure and intrinsic activity of catalysts' active sites with optimal hydrogen intermediates adsorption is crucial to enhancing the hydrogen evolution reaction (HER) in alkaline media. Herein, a heterostructured V-doped Ni 2 P/Ni 12 P 5 (V-Ni 2 P/Ni 12 P 5 ) electrocatalyst is fabricated through a hydrothermal treatment and controllable phosphidation process. In comparison with pure-phase V-Ni 2 P, in/ex situ characterizations and theoretical calculations reveal a redistribution of electrons and active sites in V-Ni 2 P/Ni 12 P 5 due to the V doping and heterointerfaces effect. The strong coupling between Ni 2 P and Ni 12 P 5 at the interface leads to an increased electron density at interfacial Ni sites while depleting at P sites, with V-doping further promoting the electron accumulation at Ni sites. This is accompanied by the change of active sites from the anionic P sites to the interfacial Ni-V bridge sites in V-Ni 2 P/Ni 12 P 5 . Benefiting from the interface electronic structure, increased number of active sites, and optimized H-adsorption energy, the V-Ni 2 P/Ni 12 P 5 exhibits an overpotential of 62 mV to deliver 10 mA cm -2 and excellent long-term stability for HER. The V-Ni 2 P/Ni 12 P 5 catalyst is applied for anion exchange membrane water electrolysis to deliver superior performance with a current density of 500 mA cm -2 at a cell voltage of 1.79 V and excellent durability.

The room‐temperature nitrogen reduction reaction (NRR) is of paramount significance for both the fertilizer industry and fundamental catalysis science. To produce ammonia from water, air, and sunlight, the photocatalytic NRR is targeted to significantly release the energy and environmental pressure associated with the current Habor–Bosch process. In this context, herein, the knowledge‐driven design of boron‐doped TiO2 is demonstrated as a photocatalyst for the nitrogen reduction reaction. Among 54 catalysts in the reported library, anatase TiO2(101) modified by boron doping is identified as an exceptional NRR catalyst with strong visible‐light absorption (bandgap 1.92 eV) and excellent reactivity with a small thermodynamic barrier (0.44 eV) as well as a high turnover frequency (1.08 × 10−5 s−1 site−1). Experimentally, the predictions of this work are validated using a B‐doped TiO2 nanosheet, achieving ammonia production with a yield of 3.35 mg h−1 g−1 under simulated sunlight irradiation, which significantly renews the performance record for Ti‐based photocatalyst for the NRR. This work highlights the importance of dual active site catalysts for nitrogen activation and reduction and demonstrates the capacity of knowledge‐driven catalyst design.

Polar surfaces of ionic crystals are of growing technological importance, with implications for the efficiency of photocatalysts, gas sensors and electronic devices. Creation of ionic nanocrystals with large percentages of polar surfaces is an option to improve their efficiency in aforementioned applications but is hard to be accomplished because they are less thermodynamically stable and prone to vanish during the growth process. Herein we developed a strategy that is capable of producing polar surface dominated II-VI semiconductor nanocrystals including ZnS and CdS, from copper sulfide hexagonal nanoplates through cation exchange reactions. The obtained hexagonal prism-shaped wurtzite ZnS hexagonal nanoplates have dominant {002} polar surfaces, occupying up to 97.8% of all surfaces. Density functional calculations reveal the polar surfaces can be stabilized by a charge transfer of 0.25 eV/formula from the anion-terminated surface to the cation-terminated surface, which also explains the presence of polar surfaces in the initial Cu1.75S hexagonal nanoplates with cation deficiency prior to cation exchange reactions. Experimental results showed that the HER activity could be boosted by the surface polarization of polar surface dominated ZnS hexagonal nanoplates. We anticipate this strategy is general and could be used to other systems to prepare nanocrystals with dominant polar surfaces. Furthermore, the availability of colloidal semiconductor nanocrystals with dominant polar surfaces produced through this strategy open a new avenue for improving their efficiency in catalysis, photocatalysis, gas sensing and other applications.

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