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Highly dispersed Co nanoparticles on biomass Juncus derived carbon achieve superb nitrite reduction performances with a faradaic efficiency of 96.9% and an NH3 yield of 2.8 mol h−1 gCo−1. The catalytic mechanism is revealed by DFT calculations.

P-doped TiO2 nanobelt array supported on titanium plate acts as a high efficiency electrocatalyst for NO2− reduction reaction, attaining a satisfactory faradaic efficiency of 90.6% and a large NH3 yield as high as 560.8 μmol h−1 cm−2.

P doping regulates the electronic conductivity of FeS2and induces charge redistribution around the doping sites to generate a local built-in electric field. As an anode in SIBs, P–FeS2@C shows superior rate performance and cycling stability.

An exquisite branch–leaf CNF@CoSSe@C was designed and fabricated, which favorably affords rich electrochemistry-active sites and multi-dimensional interconnected ion-transport channels, thus endowing superior sodium-storage lifespan over 13 000 cycles.

Rational design and development of high-efficiency electrocatalytic materials made from earth-abundant elements for H2O2 generation via a two-electron O2 reduction reaction (2e− ORR) is of crucial significance but still challenging. Here, we demonstrate that CoTe nanoparticles embedded in a nitrogen-doped hollow carbon polyhedron (CoTe@NC) can be adopted as a highly selective and stable 2e− ORR electrocatalyst. Benefiting from the synergistic effect between the highly active CoTe nanoparticles and nitrogen-doped hollow carbon polyhedron, in 0.1 M HClO4, the CoTe@NC hybrid exhibits superb electrocatalytic activity toward the 2e− ORR with high selectivity of up to 92.6% and a large H2O2 production rate of 297.9 ppm h−1 at −0.044 V versus reversible hydrogen electrode. Moreover, it operates rather stably under the working conditions with a negligible current decrease after 12 h. Theoretical calculations further provide insight into the catalytic mechanism involved.

Industrially, large-scale NH3 production mainly depends on the Haber–Bosch process, which is accompanied by heavy greenhouse gas emission and serious energy consumption. Electrochemical N2 reduction is considered a sustainable strategy to solve this problem. Herein, we report for the first time that a Mo3Si thin film sputtered on graphite paper is a favorable electrocatalyst for NH3 synthesis under ambient conditions. Electrochemical tests suggest a large NH3 yield rate of 2 × 10−10 mol s−1 cm−2 and a high Faraday efficiency of 6.69% at −0.4 V and −0.3 V vs. a reversible hydrogen electrode, respectively, in 0.1 M Na2SO4. It also demonstrates the high electrochemical and structural stability of such a catalyst as well as excellent selectivity for NH3 generation. Density functional theory calculation reveals that the synergy of the metallic conductivity of Mo3Si and the high chemical activity of the exposed Mo ions benefits the adsorption and activation of N2, and a further proton–electron transfer reaction to produce NH3.

Hierarchical heterostructure coupling metal sulfides with carbonaceous functional support are regarded as promising anode candidates for sodium-ion batteries (SIBs) owing to their rich diffusion channels and active sites for Na+-storage, as well as strong charge redistribution features between heterointerfaces. However, achieving superior rate behaviors and ultralong cycling life remains a key challenge. Herein, starting from a well-organized ZnO microflower template, a hollow microflower-like configuration of metal sulfide ZnS/CuS encapsulated in a polydopamine-derived carbon skeleton (denoted as ZnS/CuS@C) is developed. Benefiting from the strongly synergistic coupling effect of heterostructures, this architecture affords swift Na+ immigration and robust structural tolerance, as reflected by an impressive cycling life (reversible capacity of 389.4 mA h g−1 with nearly 100% retention ratio after 700 long-term cycles at 2 A g−1) and competitive rate capability (341.0 mA h g−1 at 5 A g−1 after 1330 cycles and 282.7 mA h g−1 at an ultrahigh rate up to 10 A g−1 even after 1750 cycles). Kinetics analysis and density functional theoretical calculations elucidate that the fabrication of the heterointerface could induce large pseudocapacitive behaviors and trigger ultrafast sodiation kinetics.

Electroreduction of NO to NH3 under ambient conditions mitigates the human-caused imbalance in the global nitrogen cycle and represents a sustainable and on-site alternative to the industrial Haber–Bosch process, but its efficiency is challenged by the difficulty of identifying highly active and robust electrocatalysts for the NO reduction reaction (NORR). Herein, it is reported that a Ni2P nanosheet array on carbon paper (Ni2P/CP) acts as an efficient NORR electrocatalyst toward the highly selective hydrogenation of NO to NH3. In 0.1 M HCl, the Ni2P/CP displays a large NH3 yield of 33.47 μmol h−1 cm−2 and a fairly high faradaic efficiency of up to 76.9% at −0.2 V versus the reversible hydrogen electrode, with superb electrochemical durability under the working conditions. A proof-of-concept device consisting of a Zn–NO battery with Ni2P/CP as the cathode was assembled to deliver a discharge power density of 1.53 mW cm−2 and an NH3 yield of 62.05 μg h−1 mgcat.−1. Theoretical calculations reveal that the Ni2P (111) surface effectively promotes NO adsorption and activation via an “acceptance–donation” mechanism, and the potential-determining step is the hydrogenation of *NO to *NOH. Additionally, the possible formation of the H2 and other byproducts were also investigated theoretically, and the results support the high selectivity of the NO-to-NH3 conversion process.

A hierarchical core–shell architecture of vertically arrayed ultrathin CuSe nanosheets decorating on hollow CuS microcages affords exceptional sodium storage performance with an admirable 303.1 mA h g−1 at 20.0 A g−1 after 1500 cycles.

Hybrid lead halide perovskites will potentially lead the future energy scenario if highly efficient cells have long-term stability. Here we combine state-of-the art mixed-cation formulations containing formamidinium (FA) and methylammonium (MA), with optimal guanidinium (Gua)/Cs ratios, enabling the realization of cells providing stability at their maximum efficiency.

Combining two different compounds into a heterostructure recently emerged as an auspicious strategy to mitigate the issues associated with the sluggish sodium diffusion kinetics of anode materials. Nevertheless, studies relating to as-designed heterostructures, so far, have not considered the matching of crystal structures between different compounds. In this work, a heterostructure between MnS and FeS2, featuring identical cubic systems and close lattice parameters, confined in one-dimensional carbon nanofibers was synthesized through electrospinning technology (denoted as MnS/FeS2@CNFs). An internal built-in electric field is generated at the interface of the heterostructure owing to differences in the bandgaps of the two compounds, and this is conducive to accelerating the Na+ diffusion kinetics and enhancing charge transport. Meanwhile, the one-dimensional carbon skeleton can effectively alleviate volume variations and prevent the aggregation of active material during the sodium storage process. As expected, the MnS/FeS2@CNFs composite delivered good rate performance (322.3 mA h g−1 at 10.0 A g−1) and excellent cycling durability (194.0 mA h g−1 at 10.0 A g−1 over 3600 cycles). In line with DFT calculations, the constructed heterojunction with a small mismatch of ∼3.9% can effectively enhance the electronic conductivity of the composite, thereby accelerating charge transfer. This work can help the development of rational design strategies for heterostructures and provide an in-depth understanding of the functions of heterostructures in the energy-storage field.

Advanced electrode materials embrace the key to the fundamental progress in rechargeable ion battery systems, which are essential to meet the finite nature of fossil fuels and the growing energy demands for clean and renewable energy. Metal phosphides in particular offer opportunities in rechargeable ion batteries owing to the extraordinarily high theoretical capacity and suitable redox potential. Notwithstanding these advantages, metal phosphides suffer from drastic volume variation during the electrochemical cycling process, resulting in relatively low capacity retention. Constructing metal phosphide–carbon heterostructures is an engrossing approach, which is because nanocarbon possesses bifunctional features that afford an electronic pathway and alleviate large volume expansion. Thus, the hybridization strategies of metal phosphides with different carbonaceous species are specifically highlighted in this review, followed by the illustration of how a robust understanding of these carbon matrixes within composites provides fundamental insights into the electronic conductivity, cycling durability, and rate capacity in metal phosphide electrodes. Meanwhile, the systematic discussion of the Li+/Na+/K+ ion storage mechanism in metal phosphides has also been expressly represented. Based on the insights, we outline the critical issues and challenges of metal phosphide/carbon heterostructures that need to be addressed to broaden their contribution in rechargeable ion batteries.

Electrosynthesis of NH3 from N2 addresses the need for renewable electricity storage and provides a promising alternative to the Haber–Bosch process. Unfortunately, it is hindered by sluggish kinetics and low faradaic efficiency (FE) due to the strong NN triple bond and competing proton reduction. Herein, we propose that the surface engineering of a CoP nanoarray supported on a titanium mesh using hydrophobic octadecanethiol (C18@CoP/TM) is an effective strategy to enhance the electrocatalytic activity of the CoP nanoarray supported on a titanium mesh for ambient N2-to-NH3 conversion. Such C18@CoP/TM offers an NH3 yield of 1.44 × 10−10 mol s−1 cm−2 and a FE of 14.03% in 0.1 M Na2SO4, surpassing its CoP/TM counterpart (0.783 × 10−10 mol s−1 cm−2, 5.83%). Moreover, C18@CoP/TM also shows steady NH3 yield and FE in a six-cycle test with high durability. Density functional theory calculations reveal that modifying CoP with a C18 layer leads to a regulated surface electronic structure, which further promotes the catalytic formation of NH3.

The selective two-electron O2 reduction reaction (2e− ORR) represents a green, mild, and on-site means of synthesizing H2O2. However, its practical feasibility depends on the development of advanced electrocatalysts, and limited experimental work has been done on non-precious-metal-based materials for the H2O2 electrogeneration in acids. Our study here introduces NiS2 nanosheets for the first time as an efficient electrocatalyst for the 2e− ORR under acidic conditions. In 0.05 M H2SO4, the NiS2 catalyst shows an onset overpotential of ∼130 mV and offers high selectivity (H2O2 percentage up to 99%). Moreover, the NiS2 catalyst attains the largest faradaic efficiency of 98% and the highest H2O2 yield rate of 109 ppm h−1 at 0.456 V and 0.156 V in the H-cell testing, respectively. The catalytic mechanism is revealed by theoretical calculations.

Pseudocapacitive electrochemical Na+-storage has been highlighted as one of the exploitable strategies for overcoming the sluggish diffusion-limited redox kinetics due to the effective structural preservation and fast ion-adsorption/desorption at the surface or quasi-surface of electrode materials. However, exploiting pseudocapacitive hosts with a micro–nano hierarchitecture and further achieving competitive pseudocapacitive contributions are still in their infancy so far. Herein, a yolk–shell NiS2/CuS hollow microspherical architecture with superb kinetically pseudocapacitive features was successfully constructed through an in situ hydrothermal sulfidation and subsequent ion-exchange route using Ni-based bimetallic (NiZn) organic frameworks (NiZn-MOFs) as a template precursor. As expected, the strongly synergistic coupling effect and hollow structural characteristic of the NiS2/CuS heterostructure enabled fast charge transfer and Na+ immigration, as well as the release of the mechanical stress/strain induced by the conversion reaction, and not unexpectedly, the NiS2/CuS electrode afforded extraordinary Na+-storage capability, including a remarkable specific capacity of 410.9 mA h g−1 after 750 cycles at 2.0 A g−1, excellent rate capability, and prolonged cyclability in terms of a remarkable 283.4 mA h g−1 even after 4200 cycles at 20.0 A g−1. More significantly, the kinetic analysis demonstrated that the electrochemical charge storage of the NiS2/CuS electrode manifested considerable pseudocapacitive contributions at all rates (90.0% to 96.9%), distinctly outperforming the previously reported NiS2-/CuS-based anodes. Furthermore, the density functional theoretical calculations suggested a fast Na+-transport kinetics and enhanced antibonding state energy level and Na2S adsorption energy due to the electronic redistribution and lattice distortion in the NiS2/CuS heterointerfaces.

Electrochemical water splitting is the most promising process to produce carbon-neutral hydrogen as an energy carrier, and hydrogen evolution reaction (HER) electrocatalysts are essential to reduce the energy barrier and improve hydrogen production efficiency. This driving force necessitates the design of HER electrocatalysts with low-cost, high-abundance, high activity and stability. In this review, we systemically summarize recent publications with critical insight into the advances of iron-based phosphides as HER electrocatalysts. Various synthesis strategies corresponding to different phosphating strategies for guiding iron phosphide design are described, followed by illustrations of how to boost FeP HER catalytic performance by enriching the accessible active sites and modifying the electronic structure. Finally, we point out several challenges and prospects, which can open up opportunities to design next-generation FeP HER electrocatalysts.

Surface passivation is a critical factor for improving the photovoltaic performance of perovskite solar cells. However, more robust principle investigations are required to build effective passivation strategies enabling high-performance perovskite solar cells. Here, it is demonstrated that a non-reactive organic polymer induces band-bending at the perovskite surface through a passivation effect, furthermore suppressing Pb0 formation at the perovskite surface. Consequently, the photovoltaic performance and stability of the perovskite solar cells can be improved. The key findings show that the polymer passivation layer can control the Fermi-level at the perovskite surface, which changes the band structure at the perovskite surface and affects carrier dynamics by suppressing non-radiative pathways. Moreover, the organic polymer can prevent degradation of the perovskite surface. By using the passivating layer, the open circuit voltage improves from 1.046 to 1.100 V, the photoconversion efficiency exceeds 21%, and the stability of the perovskite solar cells is substantially improved. The organic polymer poly(bisphenol A anhydride-co-1,3-phenylenediamine) (PEIm) was used to control the perovskite band structure, and this passivation mechanism is revealed here.

Supercapacitors (SCs) are promising for bridging the power/energy gap between conventional capacitors and batteries/fuel cells. However, challenges remain in the improvement of electrode materials toward high capacitive performance. Electrospun nanofibers, prepared via facile and low-cost electrospinning techniques, exhibit superior electrochemical performance in SCs due to their unique morphology and intriguing properties, demonstrating great potential for improving the performance of SCs. Herein, we review the recent progress in electrospun one-dimensional nanofibers as electrode materials for SCs. Three categories of electrospun electrode nanomaterials (i.e., carbon nanofibers, carbon nanofiber composites, and carbon-free transition metal oxides) are discussed with design and optimization strategies. Moreover, critical insights into the electronic conductivity, electrochemical response and durability of electrospun nanofibers are reviewed. Finally, we conclude with an outlook on how these discussions and insights open opportunities for electrospun nanofibers (as electrode materials) to expand their potential application in next-generation SCs.

Producing NH3 through the Haber–Bosch process has brought about huge energy-consumption and heavy emission of CO2. Electrochemical N2 reduction offers a promising alternative to realize N2 fixation under ambient conditions. In this paper, PdP2 nanoparticles–reduced graphene oxide (PdP2–rGO) is proposed as an efficient electrocatalyst for the N2 reduction reaction. In 0.5 M LiClO4, PdP2–rGO affords a large NH3 yield rate of 30.3 μg h−1 mgcat.−1 and a high faradaic efficiency of 12.56% at −0.1 V versus the reversible hydrogen electrode, which are much superior to those of its Pd–rGO counterpart (NH3 yield rate of 14.5 μg h−1 mgcat.−1 and FE of 4.28%). This catalyst also shows high stability. Density functional theory calculations suggest that the barriers for N2 activation and the subsequent hydrogenation process on the Pd catalyst are alleviated after alloying with P.

Industrial synthesis of NH3 relies mainly on the traditional Haber–Bosch process, which is highly energy-intensive with enormous greenhouse gas emission. Electrochemical N2 reduction provides an eco-friendly approach for energy-saving NH3 synthesis, but it requires highly efficient electrocatalysts under ambient conditions. In this communication, an MnO2-decorated Ti3C2Tx (T = F, OH) MXene nanohybrid (MnO2–Ti3C2Tx) is proposed as a highly active electrocatalyst for the N2 reduction reaction with strong durability. In addition, only the NH3 product without N2H4 can be detected during the NRR, revealing the excellent selectivity of MnO2–Ti3C2Tx for NH3 formation. A high NH3 yield of 34.12 μg h−1 mgcat−1 and a high faradaic efficiency of 11.39% are achieved at −0.55 V vs. a reversible hydrogen electrode in 0.1 M HCl. Density functional theory calculations further reveal that the unsaturated surface Mn atoms act as active sites to adsorb and activate the inert N2 molecules for the NRR process, and the rate-determining step is the first hydrogenation process.

Electrochemical N2 reduction offers an environmentally benign and sustainable approach for NH3 synthesis under ambient conditions wherein a high-efficiency electrocatalyst is paramount. In this study, we report that TiC/C nanofibers act as an efficient one-dimensional electrocatalyst for N2-to-NH3 conversion. In 0.1 M HCl, such an electrocatalyst achieves a large NH3 yield of 14.1 μg h−1 mg−1cat. and a high faradaic efficiency of 5.8% at −0.5 V vs. the reversible hydrogen electrode. Notably, this electrocatalyst also shows both high electrochemical stability and structural stability during electrolysis. Density functional theory calculations further reveal that TiC can efficiently activate N2 in an enzymatic route with a low energy barrier.

The design and development of highly active electrocatalysts for the hydrogen evolution reaction (HER) in alkaline media is of significant importance. In this communication, we report the direct growth of an ultralow-Pt-content (Pt content: 5.1 wt%) Ni(OH)2–PtO2 hybrid nanosheet array on a Ti mesh (Ni(OH)2–PtO2 NS/Ti), carried out by hydrothermal treatment of a Ni(OH)2 nanosheet array on a Ti mesh (Ni(OH)2 NS/Ti) in the presence of [PtCl6]2−. When used as a 3D catalyst electrode for the HER, the resulting Ni(OH)2–PtO2 NS/Ti exhibits superior activity with the need of an overpotential of only 31.4 mV to deliver a geometrical catalytic current density of 4 mA cm−2 in 0.1 M KOH. Remarkably, this catalyst also shows strong long-term electrochemical durability for at least 100 h with a faradaic efficiency close to 100%. Density functional theory calculations reveal that the Ni(OH)2/PtO2 interface can promote the kinetics of H2O dissociation and tune the hydrogen adsorption free energy to a more moderate value, thereby promoting the HER.

We report the design of an amorphous cobalt oxide hydroxide nanosheet array with anchored platinum oxide. This electrocatalyst can efficiently catalyze the hydrogen evolution reaction with outstanding activity due to the strong synergetic effect derived from its favorable composition and structure. Density functional theory calculations further demonstrate that it can greatly reduce water dissociation barriers and tune the free energy of H* adsorption close to the optimized value.

The Haber–Bosch process enables the industrial production of NH3 from N2 and H2, but it has problems with high energy consumption and CO2 emissions. Electrochemical reduction offers an environmentally-benign and sustainable alternative for NH3 synthesis. In this communication, we describe a TiO2 nanoparticles–reduced graphene oxide hybrid (TiO2–rGO) which behaves as an efficient non-noble-metal N2 reduction reaction (NRR) electrocatalyst for N2-to-NH3 conversion with excellent selectivity. When tested in 0.1 M Na2SO4, the TiO2–rGO achieves a high faradaic efficiency of 3.3% and a large NH3 yield of 15.13 μg h−1 mgcat.−1 at −0.90 V vs. a reversible hydrogen electrode. Notably, this catalyst also shows high electrochemical stability during electrolysis and recycling tests.

Co phosphides, although highly active for the hydrogen evolution electrocatalysis in acids, still deliver inferior performance in alkalis, limiting their application in alkaline water electrolysis. Building an effective Co phosphide/(hydroxide)oxide interface could be a viable way to improve the hydrogen evolution activity of Co phosphide catalysts under alkaline conditions, which however remains unexplored and challenging. In this communication, we report the facile development of a CoP–CeO2 hybrid nanosheet film on Ti mesh (CoP–CeO2/Ti) from easily made Co3O4–CeO2via a selective phosphidation strategy. In 1.0 M KOH, such CoP–CeO2/Ti achieves a geometrical catalytic current density of 10 mA cm−2 at a pretty low overpotential of 43 mV, 27 mV less than that for CoP/Ti. Remarkably, our CoP–CeO2/Ti also shows superior durability over CoP/Ti, suggesting that CeO2 greatly stabilizes the CoP catalyst. Density functional theory calculations demonstrate that CoP–CeO2 possesses a lower water dissociation free energy and a more optimal hydrogen adsorption free energy than CoP. This selective phosphidation strategy is universal in engineering the transition metal phosphide/oxide interface for applications.

Developing high-performance water oxidation electrocatalysts working under mild conditions is highly desirable, but still remains challenging. In this communication, we report the in situ surface derivation of an Fe–Co–Bi layer (4–7 nm in thickness) on an Fe-doped Co3O4 nanowire array supported on carbon cloth (Fe–Co3O4/CC). As a 3D catalyst electrode for water oxidation, such a core–shell Fe–Co3O4@Fe–Co–Bi nanoarray (Fe–Co3O4@Fe–Co–Bi/CC) demonstrates superior activity over that of a Co3O4-derived nanoarray catalyst, with the need of an overpotential of 420 mV to drive a geometrical catalytic current density of 10 mA cm−2 in 0.1 M potassium borate (pH = 9.2). Notably, this catalyst also shows good long-term stability with high turnover frequencies.

Large pore three-dimensional cage-type mesoporous carbon nitride semiconductors were successfully synthesized by employing SBA-16 templates which are prepared by hydrothermal methods at higher temperatures. These samples were characterized by using various techniques, and their photocatalytic H2 production properties were investigated under visible light (λ > 420 nm) irradiation. The results have shown that the textural parameters of the carbon nitride semiconductors can be easily tuned by simple adjustment of the synthesis temperature of the template SBA-16 silica, and carbon nitride semiconductors can be truly reversely replicated from the cubic structure of the template silica synthesized at a temperature of 180 and 200 °C. The large pore cage-type mesoporous carbon nitride semiconductor cast from mesoporous silica at the hydrothermal temperature of 200 °C exhibits a remarkably enhanced photocatalytic activity towards hydrogen evolution, as compared to either disordered mesoporous g-CN or bulk g-CN prepared by our previous synthetic approaches.

In this communication, we first report a fast and low-temperature preparation of Se doped Fe2O3 (Se-Fe2O3) nanorod arrays grown on a Ti plate with superior photoelectrochemical (PEC) performance for water oxidation. The Se-Fe2O3 offers a photocurrent density of 1.44 mA cm−2 at 1.23 V vs. the RHE in 1.0 M NaOH under simulated light (AM 1.5 G, 100 mW cm−2) irradiation, 3.13 times that of undoped Fe2O3, with a 90 mV cathodic shift of the onset potential. Experimental studies indicate that the superior PEC activity is ascribed to the increased electrical conductivity and carrier density arising from Se doping, which is of great benefit to improve the charge separation efficiency in bulk Se-Fe2O3. The present Se-doping offers an attractive approach to fabricate high-performance semiconductor photoanodes for applications.

Developing non-noble-metal hydrogen evolution reaction electrocatalysts with high activity is critical for future renewable energy systems. Here we describe the development of a self-supported NiMoS4 nanosheet array on Ti mesh (NiMoS4/Ti) through a facile two-step hydrothermal strategy. As a 3D nanoarray electrode for electrochemical hydrogen evolution, NiMoS4/Ti shows exceptionally high catalytic activity and strong durability in 0.1 M KOH (pH: 13). It needs overpotentials of only 194 and 263 mV to drive geometrical catalytic current densities of 10 and 50 mA cm−2, respectively. Moreover, such a catalyst also demonstrates superior long-term stability with a high turnover frequency of 0.75 mol H2 s−1 at an overpotential of 148 mV. Density functional theory calculations suggest a more favorable hydrogen adsorption free energy on the NiMoS4 surface.

It is of great importance but still remains a key challenge to develop non-noble-metal bifunctional catalysts for efficient full water splitting under mild pH conditions. In this communication, we report the in situ electrochemical development of an ultrathin Ni–Bi layer on a metallic Ni3N nanosheet array supported on a Ti mesh (Ni3N@Ni–Bi NS/Ti) as a durable 3D core/shell structured nanoarray electrocatalyst for water oxidation at near-neutral pH. The Ni3N@Ni–Bi NS/Ti demands overpotentials of 405 and 382 mV to deliver a geometrical catalytic current density of 10 mA cm−2 in 0.1 and 0.5 M K–Bi (pH: 9.2), respectively, superior in activity to Ni3N NS/Ti and most reported non-precious metal catalysts under benign conditions. It also performs efficiently for the hydrogen evolution reaction requiring an overpotential of 265 mV for 10 mA cm−2 and its two-electrode electrolyser affords 10 mA cm−2 at a cell voltage of 1.95 V in 0.5 M K–Bi at 25 °C.

It is highly desirable but still remains a big challenge to develop earth-abundant bifunctional catalysts for urea oxidation and hydrogen evolution electrocatalysis towards more energy-efficient electrolytic hydrogen generation. In this study, we report that nickel phosphide nanoflake arrays on carbon cloth (Ni2P NF/CC) behave as a highly-active durable 3D catalyst electrode for the urea oxidation reaction (UOR) with the required potential of 0.447 V to achieve a geometrical catalytic current density of 100 mA cm−2 in a 1.0 M KOH with 0.5 M urea. Remarkably, the high hydrogen evolution reaction (HER) activity of Ni2P NF/CC enables it to be a bifunctional catalyst for both the UOR and HER towards energy-saving electrochemical hydrogen production, and its two-electrode alkaline electrolyzer requires a cell voltage of only 1.35 V to attain 50 mA cm−2, which is 0.58 V less compared with that required for pure water splitting to achieve the same current density, with remarkable long-term electrochemical durability and nearly 100% Faradaic efficiency for hydrogen evolution.

The efficiency of perovskite solar cells based on mesoscopic TiO2 has been soaring over the past three years and is expected to reach over 25% by engineering the composition of perovskite and interface layers. Efforts to increase the power conversion efficiency (PCE) of planar junction perovskite solar cells have been made from different perspectives. For the first time, we use the wormhole-like hexagonal mesoporous silica (HMS) to modify the substrate surface inside the planar junction perovskite solar cell to improve efficiency. The formed random islands of HMS decreased the loading of the perovskite layer, leading to abnormal growth of perovskite and increased light path length. Using HMS islands in a planar heterojunction device, we realized an average PCE of 17.6% over 30 devices, which is higher than that of the controlled intrinsic planar heterojunction device (15.85%).

Exploitation of efficient water oxidation electrocatalysts under benign conditions is of great importance but remains a huge challenge. In this communication, we report the preparation of a cobalt-borate nanosheet array on a Ti mesh (Co-Bi/Ti) successfully converted from an electrodeposited α-Co(OH)2 nanosheet array in potassium borate (K-Bi) via in situ electrochemical tuning. The Co-Bi/Ti shows high electrocatalytic activity toward water oxidation with an overpotential of 469 mV to achieve a current density of 10 mA cm−2 in 0.1 M K-Bi, with long-term electrochemical stability with a turnover frequency of 0.15 s−1 at an overpotential of 600 mV.

Correction for ‘Cation optimization for burn-in loss-free perovskite solar devices’ by Sanghyun Paek et al., J. Mater. Chem. A, 2021, 9, 5374–5380, DOI: 10.1039/D1TA00472G.

Hydrogen can be catalytically generated on a large scale by hydrolysis of NaBH4. In this communication, we describe the development of cobalt phosphide nanosheet arrays on Ti mesh (CoP/Ti mesh) as a robust and highly active monolithic catalyst for the hydrolytic dehydrogenation of NaBH4 in alkaline solutions. A hydrogen generation rate of 6100 mL(H2) min−1 g(CoP)−1 and an activation energy of 42.01 kJ mol−1 were achieved under air-saturated atmospheric conditions, which are superior to those of most reported catalysts, with good durability and reusability.

Electrochemical water splitting offers an environmentally friendly route for scalable production of hydrogen fuel but demands low-cost, efficient and robust electrocatalysts for the hydrogen evolution reaction (HER). In this communication, for the first time, we report on the development of a self-standing MoP2 nanosheet array on carbon cloth (MoP2 NS/CC) topotactically converted from its MoS2 NS/CC precursor through a phosphidation reaction. When used as a novel 3D HER cathode in acids, the resulting MoP2 NS/CC shows exceptionally high catalytic activity and strong durability, which only demands an overpotential of 58 mV to drive 10 mA cm−2. Moreover, it also shows high activity and durability in basic and neutral media with the need for overpotentials of only 67 and 85 mV to achieve 10 mA cm−2, respectively. This MoP2 NS/CC catalytic electrode offers us an attractive catalyst material for water-splitting devices for large-scale hydrogen production.

Ammonia borane (AB) has been considered as one of the most attractive candidates for chemical hydrogen-storage materials; it is highly desirable but still remains a huge challenge to design and develop highly active robust non-noble-metal catalysts for on-demand hydrogen generation from AB. In this work, we demonstrate that a Ni2P nanosheet array integrated on 3D Ni foam is highly active and robust for the hydrolytic dehydrogenation of AB. This monolithic catalyst behaves as an on/off switch for on-demand hydrogen generation with a large initial turnover frequency of 42.3 mol(H2) mol(Ni2P)−1 min−1 and a lower activation energy of 44.0 kJ mol−1 under ambient conditions, outperforming all reported Ni-based noble-metal-free catalysts and some noble-metal catalysts.

There is an urgent need for active and cost-effective catalysts for electrochemical hydrogen evolution reactions to solve global energy issues. In this study, we report the development of interconnected urchin-like cobalt phosphide microspheres film on Ti foil (u-CoP/Ti) as a monolithic hydrogen-evolving catalyst electrode with high activity and strong durability under acidic and alkaline conditions. It affords 10 mA cm−2 at overpotentials as low as 45 mV with the maintenance of its catalytic activity for at least 15 h in 0.5 M H2SO4, outperforming all reported CoP catalysts. When operated in 1.0 M KOH, u-CoP/Ti is also highly active and demands overpotential of 60 mV to drive 10 mA cm−2 with strong durability.

The efficiency of water splitting is mainly limited by the low rate of the oxygen evolution reaction (OER) and it is thus of great importance but still remains a huge challenge to develop efficient OER catalysts capable of delivering high current densities at low overpotentials. Herein, we describe our recent finding that a Fedoped Ni3S2 particle film with 11.8% Fe-content hydrothermally grown on nickel foam (Fe-11.8%-Ni3S2/NF) behaves as a highly active robust oxygen evolution electrode in strongly alkaline media. This electrode needs an overpotential of only 253 mV to achieve 100 mA cm(-2) with a Tafel slope of 65.5 mV dec(-1) and maintains its catalytic activity for at least 14 h in 1 M KOH, and the NiOOH and FeOOH formed at the Fe-11.8%-Ni3S2 surface are the actual catalytic sites. Notably, it also operates efficiently and stably in 30 wt% KOH, capable of affording very high current densities of 500 and 1000 mA cm(-2) at small overpotentials of 238 and 269 mV, respectively, with a faradaic efficiency of 100%.

Large-scale industrial application of electrochemical water splitting calls for remarkable non-noble metal electrocatalysts. Herein, we report on the synthesis of a NiMo-alloy hollow nanorod array supported on Ti mesh (NiMo HNRs/TiM) using a template-assisted electrodeposition method. The NiMo HNRs/TiM behaves as a durable efficient oxygen evolution anode with 10 mA cm−2 at an overpotential of 310 mV in 1.0 M KOH. Coupled with its superior catalytic performance for hydrogen evolution with 10 mA cm−2 at an overpotential of 92 mV, we made an alkaline electrolyzer using this bifunctional electrode with 10 mA cm−2 at a cell voltage of 1.64 V.

In this paper, nanostructured CoP with different morphologies, including nanowires, nanosheets and nanoparticles, were prepared through an organic solvent-free low-temperature phosphidation reaction under Ar. These nanostructures were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Brunauer–Emmett–Teller specific surface area measurements. We further studied their electrocatalytic properties towards the hydrogen evolution reaction in acidic media and found that CoP nanowires exhibited the highest catalytic activity and stability.

Uniform core–shell composites with cage-like mesoporous silica (CmesoSiO2) shells and zeolite HZSM-5 cores have been synthesized by a facile acid-catalyzed sol–gel coating process. The mesoporous silica shells are uniform and coated on the anisotropic HZSM-5 crystal faces, and the shell-thicknesses can be tuned from 25 to 70 nm. The core–shell composites possess a high surface area (∼862 m2 g−1) and pore volume (∼0.66 cm3 g−1), large pore sizes (3.2–8.2 nm) and unchanged zeolite micropore properties. The silica shells are composed of cage-like mesopores and entrances (ranging from 3.2 to 8.2 nm) as well as a plenty of micropores. Pt nanocatalysts with an average particle size of ∼3.2 nm have been successfully encapsulated into the micropores and partial mesopores of the cage-like silica shells. The catalytic oxidation of toluene shows that the Pt/HZ@CmesoSiO2 composite presents an equivalent activity for toluene combustion at the light-off temperature of ∼195 °C (T50%) relative to the mixture catalyst (198 °C of T50%), but more excellent catalytic durability without activity loss (193 °C of T50%) after a 100 h test.