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The high theoretical energy density (1274 Wh kg−1) and high safety enable the all‐solid‐state Na−S batteries with great promise for stationary energy storage system. However, the uncontrollable solid–liquid‐solid multiphase conversion and its associated sluggish polysulfides redox kinetics pose a great challenge in tunning the sulfur speciation pathway for practical Na−S electrochemistry. Herein, we propose a new design methodology for matrix featuring separated bi‐catalytic sites that control the multi‐step polysulfide transformation in tandem and direct quasi‐solid reversible sulfur conversion during battery cycling. It is revealed that the N, P heteroatom hotspots are more favorable for catalyzing the long‐chain polysulfides reduction, while PtNi nanocrystals manipulate the direct and full Na2S4 to Na2S low‐kinetic conversion during discharging. The electrodeposited Na2S on strongly coupled PtNi and N, P‐codoped carbon host is extremely electroreactive and can be readily recovered back to S8 without passivation of active species during battery recharging, which delivers a true tandem electrocatalytic quasi‐solid sulfur conversion mechanism. Accordingly, stable cycling of the all‐solid‐state soft‐package Na−S pouch cells with an attractive specific capacity of 876 mAh gS−1 and a high energy of 608 Wh kgcathode−1 (172 Wh kg−1, based on the total mass of cathode and anode) at 60 °C are demonstrated. [ABSTRACT FROM AUTHOR]

The electrochemical CO2 reduction reaction to produce CO is one of the most promising pathways to eliminate CO2 emissions and store intermittent energy sources. However, the most critical usage of CO is via mixing with H2 to form syngas, which is a crucial feedstock for many value‐added chemicals. Therefore, producing syngas with a suitable CO/H2 ratio in a one‐step reaction is desirable in the CO2RR process. To achieve this end, dual single‐atom sites supported by the nitrogen‐doped carbon show great potential. Herein, we show that a dual single‐atom catalyst with Bi−N4 and Zn−N4 units is efficient for generating syngas with tunable CO/H2 ratios (0.20 to 2.92), which is of great significance to downstream industrial production. Moreover, this work highlights the potential to control the CO/H2 ratios for efficient syngas production using the coexisting single‐atom sites. [ABSTRACT FROM AUTHOR]

Multinary chalcogenide semiconductors (MCSs) recently emerged as a promising alternative to their binary counterparts for designing innovative solar energy conversion platforms due to a number of advantages including high absorption coefficient over a broad spectral range, conveniently tunable band structures through alloying, and nontoxicity for their use in real-world settings. The integration of MCSs with plasmonic metals into heteronanostructures is essential for promoting their light harvesting and conversion performance; however it is constrained by the large synthetic impediment arising from the incompatible activities of multiple precursors involved in growing the MCS domain via direct synthesis. Here using Au@Ag2ZnSnS4 core–shell nanocrystals (NCs) as a proof-of-concept demonstration, we report a new synthetic tactic based on cation exchange to access metal@MCS hybrid NCs with exceptional uniformity and precise control over the structural characteristics (both dimensions and morphology) in an aqueous environment. The prepared materials were explored as photoanodes for photoelectrochemical (PEC) hydrogen evolution, and the results suggested that our approach offers a good opportunity to unravel the delicate links between solar energy conversion efficiency and the structure of metal@MCS NCs. In view of the great versatility of cation exchange, we envision that this approach can be extended to fabricate a wide variety of metal@MCS NCs with unprecedented structures and functions. [ABSTRACT FROM AUTHOR]

High-activity electrocatalysts with robust structure are critical for development of renewable-energy technologies. Herein, a hybrid of cobalt nanoparticles embedded in N-doped carbon nanotubes (Co@NCNT) was fabricated via economically scalable pyrolysis of a mixture of a Co-based metal–organic framework (ZIF-67) and dicyandiamide. The as-synthesized Co@NCNT hybrid was characterized by techniques of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photon spectroscopy (XPS) etc., confirming that it possessed desirable properties of high surface area, robust structure, and good conductivity. A series of electrochemical measurements demonstrated that the Co@NCNT exhibits high activity and excellent durability toward several important electrochemical reactions, including hydrogen evolution reaction (HER) in pH-universal electrolyte, oxygen reduction reaction (ORR) in both acidic and alkaline media, glucose oxidation reaction (GOR), and oxygen evolution reaction (OER) in alkaline medium, mainly as a result of the synergistic effects of unique structure and high surface area of the Co nanoparticles and nitrogen dopant in the nanocomposite. A zinc–air battery with outstanding performance was set up using the Co@NCNT as cathode material, demonstrating its potential applications in energy storage and as a conversion system device. [ABSTRACT FROM AUTHOR]

The high theoretical energy density (1274 Wh kg -1 ) and high safety enable the all-solid-state Na-S batteries with great promise for stationary energy storage system. However, the uncontrollable solid-liquid-solid multiphase conversion and its associated sluggish polysulfides redox kinetics pose a great challenge in tunning the sulfur speciation pathway for practical Na-S electrochemistry. Herein, we propose a new design methodology for matrix featuring separated bi-catalytic sites that control the multi-step polysulfide transformation in tandem and direct quasi-solid reversible sulfur conversion during battery cycling. It is revealed that the N, P heteroatom hotspots are more favorable for catalyzing the long-chain polysulfides reduction, while PtNi nanocrystals manipulate the direct and full Na 2 S 4 to Na 2 S low-kinetic conversion during discharging. The electrodeposited Na 2 S on strongly coupled PtNi and N, P-codoped carbon host is extremely electroreactive and can be readily recovered back to S 8 without passivation of active species during battery recharging, which delivers a true tandem electrocatalytic quasi-solid sulfur conversion mechanism. Accordingly, stable cycling of the all-solid-state soft-package Na-S pouch cells with an attractive specific capacity of 876 mAh g S -1 and a high energy of 608 Wh kg cathode -1 (172 Wh kg -1 , based on the total mass of cathode and anode) at 60 °C are demonstrated., (© 2024 Wiley‐VCH GmbH.)

Li-O 2 batteries (LOBs) are considered as one of the most promising energy storage devices due to their ultrahigh theoretical energy density, yet they face the critical issues of sluggish cathode redox kinetics during the discharge and charge processes. Here we report a direct synthetic strategy to fabricate a single-atom alloy catalyst in which single-atom Pt is precisely dispersed in ultrathin Pd hexagonal nanoplates (Pt 1 Pd). The LOB with the Pt 1 Pd cathode demonstrates an ultralow overpotential of 0.69 V at 0.5 A g -1 and negligible activity loss over 600 h. Density functional theory calculations show that Pt 1 Pd can promote the activation of the O 2 /Li 2 O 2 redox couple due to the electron localization caused by the single Pt atom, thereby lowering the energy barriers for the oxygen reduction and oxygen evolution reactions. Our strategy for designing single-atom alloy cathodic catalysts can address the sluggish oxygen redox kinetics in LOBs and other energy storage/conversion devices.

Nickel-based catalysts have been regarded as one of the most promising electrocatalysts for urea oxidation reaction (UOR), however, their activity is largely limited by the inevitable self-oxidation reaction of Ni species (NSOR) during the UOR. Here, we proposed an interface chemistry modulation strategy to trigger the occurrence of UOR before the NSOR via constructing a 2D/2D heterostructure that consists of ultrathin NiO anchored Ru-Co dual-atom support (Ru-Co DAS/NiO). Operando spectroscopic characterizations confirm this unique triggering mechanism on the surface of Ru-Co DAS/NiO. Consequently, the fabricated catalyst exhibits outstanding UOR activity with a low potential of 1.288 V at 10 mA cm -2 and remarkable long-term durability for more than 330 h operation. DFT calculations and spectroscopic characterizations demonstrate that the favorable electronic structure induced by this unique heterointerface endows the catalyst energetically more favorable for the UOR than the NSOR., (© 2023 Wiley-VCH GmbH.)

Manipulating the coordination environment of the active center via anion modulation to reveal tailored activity and selectivity has been widely achieved, especially for carbon-based single-atom site catalysts (SACs). However, tuning ligand fields of the active center by single-site metal cation regulation and identifying the effects on the resulting electronic configuration is seldom explored. Herein, we propose a single-site Ru cation coordination strategy to engineer the electronic properties by constructing a Ru/LiCoO 2 SAC with atomically dispersed Ru-Co pair sites. Benefitting from the strong electronic coupling between Ru and Co sites, the catalyst possesses an enhanced electrical conductivity and achieves near-optimal oxygen adsorption energies. Therefore, the optimized catalyst delivers superior oxygen evolution reaction (OER) activity with low overpotential, the high mass activity of 1000 A g oxide -1 at a small overpotential of 335 mV, and excellent long-term stability. It also exhibits rapid kinetics with superior rate capability and outstanding durability in a zinc-air battery., (© 2022 Wiley-VCH GmbH.)

The renewable energy-powered electrolytic reduction of carbon dioxide (CO 2 ) to methane (CH 4 ) using water as a reaction medium is one of the most promising paths to store intermittent renewable energy and address global energy and sustainability problems. However, the role of water in the electrolyte is often overlooked. In particular, the slow water dissociation kinetics limits the proton-feeding rate, which severely damages the selectivity and activity of the methanation process involving multiple electrons and protons transfer. Here, we present a novel tandem catalyst comprising Ir single-atom (Ir 1 )-doped hybrid Cu 3 N/Cu 2 O multisite that operates efficiently in converting CO 2 to CH 4 . Experimental and theoretical calculation results reveal that the Ir 1 facilitates water dissociation into proton and feeds to the hybrid Cu 3 N/Cu 2 O sites for the *CO protonation pathway toward *CHO. The catalyst displays a high Faradaic efficiency of 75% for CH 4 with a current density of 320 mA cm -2 in the flow cell. This work provides a promising strategy for the rational design of high-efficiency multisite catalytic systems.

The in-depth understanding of local atomic environment-property relationships of p-block metal single-atom catalysts toward the 2 e - oxygen reduction reaction (ORR) has rarely been reported. Here, guided by first-principles calculations, we develop a heteroatom-modified In-based metal-organic framework-assisted approach to accurately synthesize an optimal catalyst, in which single In atoms are anchored by combined N,S-dual first coordination and B second coordination supported by the hollow carbon rods (In SAs/NSBC). The In SAs/NSBC catalyst exhibits a high H 2 O 2 selectivity of above 95 % in a wide range of pH. Furthermore, the In SAs/NSBC-modified natural air diffusion electrode exhibits an unprecedented production rate of 6.49 mol peroxide g catalyst -1  h -1 in 0.1 M KOH electrolyte and 6.71 mol peroxide g catalyst -1  h -1 in 0.1 M PBS electrolyte. This strategy enables the design of next-generation high-performance single-atom materials, and provides practical guidance for H 2 O 2 electrosynthesis., (© 2022 Wiley-VCH GmbH.)

The electrocatalytic reduction reaction of CO 2 (CO 2 RR) is a promising strategy to promote the global carbon balance and combat global climate change. Herein, exclusive Bi-N 4 sites on porous carbon networks can be achieved through thermal decomposition of a bismuth-based metal-organic framework (Bi-MOF) and dicyandiamide (DCD) for CO 2 RR. Interestingly, in situ environmental transmission electron microscopy (ETEM) analysis not only directly shows the reduction from Bi-MOF into Bi nanoparticles (NPs) but also exhibits subsequent atomization of Bi NPs assisted by the NH 3 released from the decomposition of DCD. Our catalyst exhibits high intrinsic CO 2 reduction activity for CO conversion, with a high Faradaic efficiency (FE CO up to 97%) and high turnover frequency of 5535 h -1 at a low overpotential of 0.39 V versus reversible hydrogen electrode. Further experiments and density functional theory results demonstrate that the single-atom Bi-N 4 site is the dominating active center simultaneously for CO 2 activation and the rapid formation of key intermediate COOH* with a low free energy barrier.