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Single metal atoms decorated on earth‐abundant transition‐metal‐based supports have attracted intensive attention toward oxygen evolution reaction (OER) due to their decent activity and low cost. However, further optimizing the catalytic performance is severely plagued by the limited active sites. Conventional optimization relies primarily on increasing the metal loading but is extremely difficult. Thus, it is imperative to go beyond the current design paradigms. Herein, it is reported that the anchored highly active single metal atoms can reinforce the electrochemical reconstruction of the supports and thus yield more substrate active sites. Consequently, increased amount of active sites and enhanced intrinsic activity can be readily realized simultaneously. Taking Ni2P4O12 decorated with single Ir atoms as a typical example, an extraordinary activity of η10 = 186 mV and η100 = 238 mV and robust stability up to 108 h are achieved. Mechanistic study uncovers that the reinforced reconstruction of Ni2P4O12 originates from the promoted PO43− leaching by single Ir atoms, which is an intrinsic feature of the supports to achieve such reinforcement. The proposed concept, decorating single metal atoms on supports featured by facile anion leaching, opens a new avenue to the design of practical electrocatalysts for efficient OER. [ABSTRACT FROM AUTHOR]

Artificial photosynthesis in carbon dioxide (CO2) conversion into value-added chemicals attracts considerable attention but suffers from the low activity induced by sluggish separation of photogenerated carriers and the kinetic bottleneck-induced unsatisfied selectivity. Herein, we prepare a new-style Bi/TiO2 catalyst formed by pinning bismuth clusters on TiO2 nanowires through being confined by pores, which exhibits high activity and selectivity towards photocatalytic production of CH4 from CO2. Boosted charge transfer from TiO2 through Bi to the reactants is revealed via in situ X-ray photon spectroscopy and time-resolved photoluminescence (PL). Further, in situ Fourier transform infrared results confirm that Bi/TiO2 not only overcomes the multi-electron kinetics challenge of CO2 to CH4 via boosting charge transfer, but also facilitates proton production and transfer as well as the intermediates ⋆CHO and ⋆CH3O generation, ultimately achieving the tandem catalysis towards methanation. Theoretical calculation also underlies that the more favorable reaction step from ⋆CO to ⋆CHO on Bi/TiO2 results in CH4 production with higher selectivity. Our work brings new insights into rational design of photocatalysts with high performance and the formation mechanism of CO2 to CH4 for solar energy storage in future. [ABSTRACT FROM AUTHOR]

The intrinsic flexoelectric effect observed in oxide materials often falls below the desired threshold for practical applications. In this work, we demonstrate proton doping in insulating rutile TiO2 crystal as an effective approach to significantly increase flexoelectricity by more than two orders of magnitude. We attribute the noteworthy enhancement of flexoelectricity to the dual impact of proton doping in oxide materials. First, proton doping serves to induce the presence of charge carriers, resulting in the generation of flexoelectric currents. Second, proton doping induces expansion and distortion of the lattice structure, leading to an amplified flexoelectric field when the crystal experiences a strain gradient. The formation of O–H bonding in TiO2 crystal provides another route to break centrosymmetry according to lattice distortion of the TiO2 lattice, resulting in a larger flexoelectric field. In addition, the introduction of proton doping in TiO2 single crystals leads to a substantial increase in photocurrent by effectively flattening the interfacial Schottky junction. This phenomenon results in a three-order of magnitude enhancement of the photocurrent. Our work broadens the horizon of study on dielectric materials through proton doping and may also provide an approach that enables the utilization of dielectric materials in energy conversion applications. [ABSTRACT FROM AUTHOR]

Recently, the bismuth‐rich strategy via increasing the bismuth content has been becoming one of the most appealing approaches to improve the photocatalytic performance of bismuth oxyhalides. However, insights into the mechanism behind the encouraging experiments are missing. Herein, we report the results of the theory‐led comprehensive picture of bismuth‐rich strategy in bismuth oxyhalide photocatalysts, selecting Bi5O7X (X = F, Cl, Br, I) as a prototype. First‐principle calculations revealed that the strategy enables good n‐type conductivity, large intrinsic internal electric field, high photoreduction ability and outstanding harvest of visible light, and particularly ranked the intrinsic activity of this family: Bi5O7F > Bi5O7I > Bi5O7Br > Bi5O7Cl. Designed experiments confirmed the theoretical predictions, and together, these results are expected to aid future development of advanced photocatalysts. [ABSTRACT FROM AUTHOR]

Piezo-electrocatalysis based on the non-centrosymmetric materials opens an avenue for mechano-to-H2 production through harvesting mechanical energy, being undergoing significant growth. Direct comparison of the performance of various piezo-electrocatalysts is necessary to obtain the optimal candidates for satisfying the demands of practical application but remains a grand challenge because the acquiescently added sacrificial agents vary considerably in the literature. Herein, we systematically investigate the effect of four commonly used types containing totally 15 sacrificial agents on the piezo-electrocatalytic hydrogen evolution by choosing the typical BaTiO3 catalyst as the demo. It is found that the pH, length of the carbon chain, adsorption strength between catalysts and sacrificial agent, and combination of sacrificial agents would impact on the piezo-electrocatalytic H2 evolution performance. Moreover, the self-decomposition effect is found in the sacrificial agent-water mixtures under ultrasonic vibration, implying that H2 can be generated without piezo-electrocatalysts, which was usually ignored. Thus, in this work, a concept of net H2 yield is suggested to standardize the evaluation of piezo-electrocatalysts in future. [ABSTRACT FROM AUTHOR]

Ultrasound-stimulated piezo-electrocatalysis has been studied for a period; however, the mechanism is still unclear mainly due to the coexistence with other multiple effects like sonocatalysis, which was usually ignored. In this work, with the non-piezoelectric H2Ti3O7 nanowires following the same experimental process in piezo-electrocatalysis, the sonocatalytic reduction performance of CO2 is investigated. By applying vibration under the excitation of ultrasound with various frequencies and powers, it is found that CO is the ultimate product with a selectivity of 100%, and the optimal CO yield of 8.3 μmol g−1 h−1 is achieved with the addition of sacrificial agents. The H2Ti3O7 catalysts are also found to present a good recycling utilization ability. This work indicates that the sonocatalysis effect may exist in the piezo-electrocatalytic process using the ultrasonic excitation, which is suggested to be taken into consideration when exploring the mechanism of piezo-electrocatalysis in the future. [ABSTRACT FROM AUTHOR]