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Perovskite oxides are a class of attractive materials for their broad applications in many energy conversion and storage fields, while their catalytic performance of CO2 electroreduction (CO2ER) has been rarely investigated. Herein, all-inorganic SrSnO3 perovskite nanowires are constructed and utilized to catalyze the CO2ER for the first time. Inspiringly, such SrSnO3 NWs demonstrates impressive selectivity and activity for formate production, with considerable Faradaic efficiencies (~80%) over a broad potential range, and the highest formate partial current density of 21.6 mA cm−2, much better than that of the SnO2 nanoparticles. Further analyses reveal that the notable CO2ER activity of SrSnO3 NWs is linked to the efficient stabilization of formate intermediate (CO2•−) as well as the slow kinetics for hydrogen evolution reaction (HER). This work can inspire the development of highly efficient perovskite catalysts for CO2ER and beyond.

While electrochemical carbon dioxide reduction reaction (CO2RR) is a highly desirable approach for converting CO2 into highly-valued fuels and chemicals, the design and create of efficient CO2RR catalysts with excellent selectivity to desirable product and long-term stability still remains great challenge. In this work, we have successfully created a series of bimetallic CuSn nanowires (NWs) with modulated phases and structures as superior electrocatalysts for CO2RR. Three distinct CuSn NWs, namely, CuSn NWs/C-Air, CuSn NWs/C-H2 and CuSn NWs/C-N2, have been created by the combination of hydrothermal process and controlled thermal treatment in different atmospheres, where the optimized CuSn NWs/C-Air shows significant enhanced activity with the best formate selectivity of 90.2% at −1.0 V versus reversible hydrogen electrode under alkaline condition, which is much higher than those of CuSn NWs/C-H2 (62.6%) and CuSn NWs/C-N2 (64.3%). Moreover, the unique CuSn NWs/C-Air also exhibits enhanced stability without significant activity and selectivity degradation after continuous operating about 10 h. Density functional theory calculations reveal that Sn atoms doping into CuO(111) surface, enhancing the adsorption of CO2 intermediate *OCHO and suppressing H2 production, could be the plausible site to realize the high selective CO2RR observed in CuSn NWs/C-Air. The realization of one-dimensional (1D) heterostructures with precisely modulated phases and structures hold significant promise for the design of efficient electrocatalysts and beyond.

The methanol (CH3OH) crossover in direct methanol fuel cells is very poisonous to cathodic noble metal electrocatalysts, which usually leads to serious degradation of electrocatalytic performance. However, most focus of present research has been concentrated on the persistent pursuit of enhancing the sluggish ORR reactions while the pivotal methanol crossover has been left out generally. The “reactivity and anti-poison” dilemma has been approached by many surface engineering including the development of new membrane with low methanol permeability or assemble layered structures. As the notable structure-dependent performance in catalytic reaction, our work has proposed Pd@NiO core@shell as an interface engineering approach that can significantly inhibit the CO species adsorption while preserving the ORR reactivity, which can also exhibit superior stability even in poisoning circumstances. Herein, we report a series of unique Pd@NiO-x/C with controlled interface structure to overcome the activity and anti-poisoning issues of oxygen reduction reaction (ORR), where the optimized Pd@NiO/C exhibits a high activity of 0.24 A mg−1, excellent tolerance over the CH3OH/CO poisoning as well as superior stability even in the practical poisoning circumstances, all which are far better than the commercial Pt/C and Pd/C. DFT calculations reveal that the excellent ORR performance with effective methanol tolerance become superior with core@shell interfacial engineering. With effective modulations, the generalized interfacial d-band-offset can be achieved for counteracting the ORR barriers with extra-high current density. The simultaneously high activity and excellent anti-poisoning features of the Pd@NiO nanostructure make it a practically potential electrocatalyst for fuel cell and beyond.

The development of efficient bifunctional electrocatalysts for overall water splitting in acidic condition is of importance for polymer electrolyte membrane (PEM) electrolyzers, but full of challenges. Herein, we report the successful creation of a class of hollow iridium (Ir)-silver (Ag) nanotubes (NTs) via a facile selective etching approach. Because of the unique properties of hollow structure and enriched oxidized Ir on the surface, the optimized Ir6Ag9 NTs show low oxygen evolution reaction overpotentials of 285 mV and 296 mV at 10 mA/cm2 in 0.5 M and 0.05 M H2SO4, respectively, being superior to the commercial Ir/C. The Ir6Ag9 NTs also exhibit lower hydrogen evolution reaction overpotentials (only 20 mV and 34 mV at 10 mA/cm2 in 0.5 M and 0.05 M H2SO4, respectively). More significantly, the Ir6Ag9 NTs/C can be further applied as bifunctional electrocatalysts with very low cell voltage of only 1.55 V at 10 mA/cm2 in 0.5 M H2SO4 as well as excellent durability with very small activity loss after 1000 cycles, holding much potential in the practical application in proton exchange membrane water electrolyzer.

Since the interface in catalyst directly influences the catalytic performance, it is imperative to create hierarchical nanostructures with modulated atomic arrangements at the interfaces for catalysis optimization. Herein, we report an unprecedented ruthenium-nickel (Ru-Ni) heterostructure with phase-segregated sandwich-like morphology for boosting electrocatalysis. The Ru selectively grows at the two ends of the Ni pillar, in which intimate interfaces is formed between Ru and Ni domains. We found such Ru-Ni sandwiched nanoplates (SNs) are highly efficient for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline electrolytes with very low overpotentials and Tafel slopes. Significantly, the optimized Ru-Ni SNs deliver a low onset potential of only 1.45 V and enhanced durability in the overall water splitting device, indicating a promising electrocatalyst towards the practical alkaline electrolysis.

Although great advances have been achieved in the field of electrocatalysis, the design of highly efficient and stable earth-abundant electrocatalysts for overall water splitting remains a significant challenge. Herein, we have successfully developed cost-efficient three dimensional (3D) highly open hierarchical catalysts with cobalt-molybdenum nanosheet arrays on nickel foam (NF) (denoted as CoMoO NSs@NF) and CoMoP NSs@NF via phosphorization for efficient overall water splitting. The optimized Co5Mo1.0O NSs@NF exhibits excellent OER activity with low overpotentials of 270 mV at 10 mA cm−2 and superior stability after 140 h and the optimized Co5Mo1.0P NSs@NF shows excellent HER activity with low overpotential of 173 mV at 10 mA cm−2 and superior stability after 1000 CV cycles. In addition to the enhanced electron migration and mass transfer benefited from the 3D structure, the XPS analysis shows that Mo plays a vital role on modulating the number of active sites on the surface, leading to the electrocatalytic enhancement. Significantly, the Co5Mo1.0O NSs@NF//Co5Mo1.0P NSs@NF couple showed highly efficient overall water electrolysis with a low potential of 1.68 V at 10 mA cm−2 in an alkaline electrolyzer as well as excellent stability after long-term water splitting, holding great potential for practical overall water splitting electrocatalysis.

For the generation of hydrogen peroxide (H2O2), a robust electrocatalyst with high activity, selectivity and stability under pH-universal conditions is a formidable challenge. Herein, Pd4Se nanoparticles (NPs) have been proposed as a highly active, selective and durable electrocatalyst for H2O2 production over a wide pH range for the first time. In particular, the Pd4Se NPs show superior H2O2 production selectivities of 93.5%, 89.7%, and 86.7% in 0.1 M HClO4, 0.1 M KCl and 0.1 M KOH electrolytes, respectively. Density functional theory (DFT) calculations reveal that Se incorporation prevents the O O early-cleavage issue by suppressing the excessive electronegativity of the Pd sites. In addition, a strong p-d repulsive correlation shifts the Pd-4d band towards the electron-depleting centre, allowing near-barrier-free electron transfer and facilitating [OOH-] stabilization. Owing to a high energy barrier of the dissociation of [OOH-], the four-electrons oxygen reduction pathway is significantly suppressed for high H2O2 selectivity. The Pd4Se NPs are also highly stable, with only a 2.4%, 9.6% and 3.4% decrease for H2O2 selectivity in 0.1 M HClO4, 0.1 M KCl and 0.1 M KOH electrolytes, respectively, after 5000 cycles, which shows that these NPs are a unique and robust Pd-based electrocatalyst for H2O2 generation under pH-universal conditions.

Perovskites are highly promising candidates in future energy conversion and storage due to their rich diversities and readily tunable electronic properties. However, the poor morphology controllability and limited surface areas have severely limited their applications. We present a generalizable synthesis strategy to fabricate a library of one-dimensional (1D) inorganic perovskite nanomeshes via pyrolysis of metal salt-polymer fibers. Within the evaluated perovskite nanomeshes, La0.5Ba0.5Co0.8Ni0.2O3 delivers the most remarkable performance for the oxygen evolution reaction (OER). Combined X-ray absorption spectroscopy experiments and density functional theory calculations reveal that introduction of additional metals endows more flexible electronic structures to realize the electron transfer in 1D perovskite nanomeshes. This work demonstrates a scalable and retrosynthetic route to easily synthesize the inorganic perovskite nanomaterials with tunable compositions.

RuO2-based catalysts have been widely used for acidic oxygen evolution reaction (OER), a key half reaction of overall water splitting. However, RuO2 suffers from the drawbacks of inferior OER performance in acidic conditions due to its poor stability. We here demonstrate a chemical etching strategy for fabricating a Ru/Fe oxide towards OER, in which Fe species in the pristine Ru/Fe nanoassemblies (P-Ru/Fe NAs) are partially etched by nitric acid (HNO3), leading to the generation of abundant vacancies in the etched Ru/Fe oxide nanoassemblies (E-Ru/Fe ONAs). Owing to the etching of Fe, the local electron density of the lattice O associated with Ru atoms is significantly increased, resulting in the suppression of H2O adsorption on lattice O. On the other hand, the O vacancies in the E-Ru/Fe ONAs can promote the H2O adsorption on metal atoms (i.e., Ru and Fe). Consequently, the optimized E-Ru/Fe ONAs exhibit a superior OER activity with a low overpotential of 238 mV at 10 mA cm−2 in 0.5 M H2SO4, and an enhanced stability with a negligible potential change within 9 h chronopotentiometry test. Theoretical calculations demonstrate that the defective surface of E-Ru/Fe ONA can not only enhance the stability via surface structural modulation, but also optimize the binding strength of the intermediates for promoting OER activity. This work provides an efficient strategy for fabricating active and stable RuO2-based catalysts for OER, which may deepen the research in surface engineering of catalysts.

Hydrogen evolution reaction (HER), a promising strategy for converting electricity to value-added H2 fuel, is a key half reaction of the overall water splitting. However, HER is suffering from the sluggish kinetics in alkaline. We here demonstrate a highly efficient catalyst for alkaline HER via surface and interface engineering of RhOOH nanosheets (NSs). The surface structure of RhOOH NSs can be precisely tuned by altering the cyclic voltammogram cycles (CVs) in the activation process, leading to the formation of strongly synergized RhOOH/Rh interface for boosted HER activity in alkaline. The optimized catalyst exhibits a promising alkaline HER performance with overpotential of 18 mV at current density of 10 mA∙cm−2 and Tafel slope of 19.3 mV∙dec−1 in 1 M KOH, which surpasses the commercial Pt/C, Rh NSs/C and RhOOH NSs/C. Detailed experiments and theoretical calculations reveal that the synergy between RhOOH and Rh significantly promotes the H2O adsorption/dissociation to form Had and the Had desorption to produce H2.

The direct methane (CH4) conversion (DMC) to methanol (CH3OH) has been attracting great attention, however it remains a huge challenge to achieve this process because of the dilemmas in CH4 selective activation. We here report that the lichen-like RuCu nanosheets (RuxCu1-x NLs) can serve as high-efficiency catalysts to catalyze DMC to produce oxygenates (CH3OH and methylhydroperoxide (CH3OOH)) under mild conditions in the presence of oxygen (O2) and trace amount of hydrogen peroxide (H2O2). Detailed characterizations and results show that the composition-dependent synergy between Ru and Cu in the bimetallic RuCu NLs, which is related to the ratio of Ru4+ on the surface of catalysts, can strongly enhance the DMC activity. The optimized catalyst of Ru0.85Cu0.15 NLs/SiO2-300 gives superior DMC performance in terms of oxygenates yield (3241.6 μmol g−1 h−1) and selectivity (93.8%) at 50 °C. This work not only highlights the superior performance of DMC from RuxCu1-x NLs, but also promotes the potential application of Ru-based nanomaterials in heterogeneous catalysis.