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Developing low‐cost and high‐activity pH‐universal hydrogen evolution reaction (HER) catalysts is very crucial to the industrialization of water electrolysis. However, the high price, low yield, and poor stability of current HER catalysts make them difficult to meet practical requirements. Herein, a plasma spraying technique is employed to prepare self‐supported Cu catalysts with tensile strain for the first time. The tensile strain upshifts the d‐band of Cu, improves the water dissociation and H* adsorption, eventually improves the intrinsic HER catalytic activity. As such, Cu electrode achieves overpotentials of 182 mV in 0.5 m H2SO4, 261 mV in 1 M PBS, and 121 mV in 1 M KOH at 10 mA cm–2. In addition, Cu electrode also performs well at high current densities, the overpotentials at 1 A cm–2 are much lower than those of Pt foil in acid, neutral, and alkaline solutions. [ABSTRACT FROM AUTHOR]

Metallic catalysts with nanopores are advantageous on improving both activity and selectivity, while the reason behind that remains unclear all along. In this work, porous Zn nanoparticles (P‐Zn) were adopted as a model catalyst to investigate the catalytic behavior of metallic nanopores. In situ X‐ray absorption spectroscopy, in situ Fourier transform infrared spectroscopy, and density functional theory (DFT) analyses reveal that the concave surface of nanopores works like a pincer to capture and clamp CO2 and H2O precursors simultaneously, thus lowering the energy barriers of CO2 electroreduction. Resultantly, the pincer mechanism endows P‐Zn with a high Faradic efficiency (98.1 %) towards CO production at the potential of −0.95 V vs. RHE. Moreover, DFT calculation demonstrates that Co and Cu nanopores exhibit the pincer behavior as well, suggesting that this mechanism is universal for metallic nanopores. [ABSTRACT FROM AUTHOR]

Catalyst support with good conductivity and stability is an eternal pursuit in the search for a high‐performance electrocatalyst. Here, an unusual catalyst support, laser‐modified boron nitride with C, O dopants (L‐BN), for the oxygen evolution reaction is reported. L‐BN exhibits unique advantages for electrocatalysis, namely, high corrosion resistance under oxidizing conditions, enhanced electrical conductivity arising from interlayer B–B dipolar interaction, and strong interaction with IrOx catalyst caused by NCN bonds. As an excellent substrate, L‐BN helps to achieve higher activity and stability than its carbon black counterpart. [ABSTRACT FROM AUTHOR]

Developing highly efficient and low‐cost photocatalysts for overall water splitting has long been a pursuit for converting solar power into clean hydrogen energy. Herein, we demonstrate that a nonstoichiometric nickel–cobalt double hydroxide can achieve overall water splitting by itself upon solar light irradiation, avoiding the consumption of noble‐metal co‐catalysts. We employed an intensive laser to ablate a NiCo alloy target immersed in alkaline solution, and produced so‐called L‐NiCo nanosheets with a nonstoichiometric composition and O2−/Co3+ ions exposed on the surface. The nonstoichiometric composition broadens the band gap, while O2− and Co3+ ions boost hydrogen and oxygen evolution, respectively. As such, the photocatalyst achieves a H2 evolution rate of 1.7 μmol h−1 under AM 1.5G sunlight irradiation and an apparent quantum yield (AQE) of 1.38 % at 380 nm. [ABSTRACT FROM AUTHOR]

Abstract: The spin state, specifically antibonding orbital (e g) occupancy, of transition‐metal ions is recognized as a descriptor for oxygen electrocatalysts with perovskite or spinel structures, and can be facilely adjusted by varying the valence states of transition metals. However, both perovskites and spinels show unsatisfactory performance even at the optimal spin states. In comparison, some oxides with a rock salt structure (e.g., NiIICoIIO2) exhibit higher activity than perovskites and spinels, nevertheless, the rock salt structure excludes valence changes of the transition metals, obstructing further e g optimization and performance enhancement. Herein, an innovative strategy is demonstrated to regulate the spin states of CoII in NiCoO2 via crystallinity manipulation, thus providing a new strategy for eg optimization. Remarkably, the catalyst (CNO‐8) with a moderate eg occupancy (≈1.2) achieves the best electrocatalytic activity, which is among the highest achieved by the state‐of‐the‐art electrocatalysts, namely, an overpotential of ≈269 mV at 10 mA cm−2 for oxygen evolution reaction and an onset potential of 935 mV for oxygen reduction reaction. As an efficient bifunctional catalyst for rechargeable Zn‐air batteries, CNO‐8 even outperforms the noble metal catalyst (Pt/C + RuO2), demonstrating high potential for practical applications in electrochemical energy conversion. [ABSTRACT FROM AUTHOR]

GLO:OKZ/10mar20:adfm202000364-fig-0002.jpg PHOTO (COLOR): S2 a) Low-resolution transmission electron microscopy image of C-CO nanoparticles. The inset is size distribution pattern with an average particle size ~2.0 ± 0.5 nm. b) High-resolution transmission electron microscopy image of C-CO nanoparticles. gl. [Extracted from the article]

Ultrasmall size and abundant defects are two crucial factors for improving the performance of catalysts. However, it is a big challenge to introduce defects into ultrafine catalysts because of the surface tension and self‐purification effect of the nanoparticles. In the present work, physical laser fragmentation with chemical oxidization reaction is combined to synthesize Co3O4 nanoparticles (L‐CO) with ultrasmall size (≈2.1 nm) as well as abundant oxygen vacancies, thus providing an effective solution to the long‐standing contradiction between the size reduction and defect generation. The ultrasmall particle size allows more catalytic sites to be exposed. The surficial oxygen vacancies enhance the intrinsic activity, while the internal oxygen vacancies improve the electron transfer, and all of these benefits make L‐CO an active and durable bifunctional catalyst for oxygen reduction/evolutions. As the air cathode of zinc–air battery, L‐CO displays excellent rechargeable performance with a power density of ≈337 mW cm−2, outperforming the commercial noble metal couple (Pt/C+RuO2). [ABSTRACT FROM AUTHOR]

Highly efficient and stable catalysts for the hydrogen evolution reaction, especially in alkaline conditions are crucial for the practical demands of electrochemical water splitting. Here, the synthesis of a novel RuAu single‐atom alloy (SAA) by laser ablation in liquid is reported. The SAA exhibits a high stability and a low overpotential, 24 mV@10 mA cm−2, which is much lower than that of a Pt/C catalyst (46 mV) in alkaline media. Moreover, the turnover frequency of RuAu SAA is three times that of Pt/C catalyst. Density functional theory computation indicates the excellent catalytic activity of RuAu SAAs originates from the relay catalysis of Ru and Au active sites. This work opens a new avenue toward high‐performance SAAs via fast quenching of immiscible metals. [ABSTRACT FROM AUTHOR]