The electronic metal–support interaction (EMSI) plays a crucial role in catalysis as it can induce electron transfer between metal and support, modulate the electronic state of the supported metal, and optimize the reduction of intermediate species. In this work, the tailoring of electronic structure of Pt single atoms supported on N‐doped mesoporous hollow carbon spheres (Pt1/NMHCS) via strong EMSI engineering is reported. The Pt1/NMHCS composite is much more active and stable than the nanoparticle (PtNP) counterpart and commercial 20 wt% Pt/C for catalyzing the electrocatalytic hydrogen evolution reaction (HER), exhibiting a low overpotential of 40 mV at a current density of 10 mA cm−2, a high mass activity of 2.07 A mg−1Pt at 50 mV overpotential, a large turnover frequency of 20.18 s−1 at 300 mV overpotential, and outstanding durability in acidic electrolyte. Detailed spectroscopic characterizations and theoretical simulations reveal that the strong EMSI effect in a unique N1−Pt1−C2 coordination structure significantly tailors the electronic structure of Pt 5d states, resulting in promoted reduction of adsorbed proton, facilitated H−H coupling, and thus Pt‐like HER activity. This work provides a constructive route for precisely designing single‐Pt‐atom‐based robust electrocatalysts with high HER activity and durability.

Electrochemical CO 2 reduction reaction (CO2RR) to formate is considered as one of the most promising routes for value-added fuels and chemical productions. The achievement of excellent activity and high Faradaic efficiency in a wide potential range is critical for mature applications. To this regard, we first employed density functional theory simulations to predict activity of Bi nanotubes and Bi nanosheets to CO2RR and selectivity toward formate. The theoretical thermodynamic analysis of the reaction energetics suggests that the limiting potential for CO 2 reduction to HCOOH decreases with the increase of the curvature, suggesting a wider potential window of Bi nanotubes for formate formation. Then, Bi nanotubes with highly curved surface were experimentally prepared, showing a large current density (−39.4 mA cm −2 at −1.1 V vs reversible hydrogen electrode (RHE)) for CO 2 reduction and a maximum formate selectivity of 97% at −1.0 V vs RHE. More importantly, compared with Bi nanosheets, an appreciable selectivity for formate was achieved on Bi nanotubes in a significantly wider potential window of ∼600 mV (selectivity > 80%). This research provides not only the CO2RR activity−surface structure relationship of metallic Bi but also an efficient strategy for the rational design of electrocatalysts with high activity and selectivity in a wide potential window for CO2RR, which is favorable for compatible application with varied types of photovoltaics and other renewable energy sources.

Water oxidation is the key process for many sustainable energy technologies containing artificial photosynthesis and metal-air batteries. Engineering inexpensive yet active electrocatalysts for water oxidation is mandatory for the cost-effective generation of solar fuels. Herein, we propose a novel hierarchical porous Ni-Co-mixed metal sulfide (denoted as NiCoS) on TiCT MXene via a metal-organic framework (MOF)-based approach. Benefiting from the unique structure and strong interfacial interaction between NiCoS and TiCT sheets, the hybrid guarantees an enhanced active surface area with prominent charge-transfer conductivity and thus a superior activity toward oxygen evolution reactions (OERs). Impressively, the hierarchical NiCoS in the hybrid is converted to nickel/cobalt oxyhydroxide-NiCoS assembly (denoted as NiCoOOH-NiCoS) by OER measurement, where NiCoOOH on the surface is confirmed as the intrinsic active species for the consequent water oxidation. The hybrid material is further applied to an air cathode for a rechargeable zinc-air battery, which exhibits low charging/discharging overpotential and long-term stability. Our work underscores the tuned structure and electrocatalytic OER performance of MOF derivatives by the versatility of MXenes and provides insight into the structure-activity relationship for noble metal-free catalysts.

Electrochemical water splitting to produce hydrogen bears a great commitment for future renewable energy conversion and storage. By employing an in situ chemical vapor deposition (CVD) process, we prepared a bimetal (Ni and Mo) sulfide-based hybrid nanowire (NiS 2 /MoS 2 HNW), which was composed of NiS 2 nanoparticles and MoS 2 nanoplates, and revealed that it is an efficient electrocatalyst for the hydrogen evolution reaction (HER) over a wide pH range due to the collective effects of rational morphological design and synergistic heterointerfaces. On a simple glassy carbon (GC) electrode, NiS 2 /MoS 2 HNW displays overpotentials at −10 mA cm −2 catalytic current density (η 10 ) of 204, 235, and 284 mV with small Tafel slopes of 65, 58, and 83 mV dec −1 in alkaline, acidic, and neutral electrolyte, respectively, exhibiting pH-universal-efficient electrocatalytic HER performance, which is comparable to the recently reported state-of-the-art sulfide-based HER electrocatalysts. Theoretical calculations further confirm that the advantage of all-pH HER activity of NiS 2 / MoS 2 originates from the enhanced dissociation of H 2 O induced by the formation of lattice interfaces of NiS 2 −MoS 2 heterojunctions. This work can pave a valuable route for designing and fabricating inexpensive and high-performance electrocatalysts toward HER over a wide pH range.

The design and decoration of plasmonic metal hybrid photoanodes provide an effective strategy for highly efficient photoelectrochemical (PEC) water splitting. In this work, an Au nanoparticle (NP) decorated highly ordered ZnO/CdS nanotube arrays (ZnO/CdS/Au NTAs) photoanode has been rationally designed and successfully synthesized. By virtue of the favorable band alignment and specific nanotube structure of ZnO/CdS as well as the surface plasmonic effect of Au NPs, the ZnO/CdS/Au NTAs photoanode shows significantly enhanced PEC performance as compared to the ZnO/CdS/Au and ZnO/CdS nanorod arrays (NRAs). Impressively, the optimized ZnO/CdS/Au NTAs photoanode exhibits the highest photocurrent density of 21.53 mA/cm2 at 1.2 V vs Ag/AgCl and 3.45% photoconversion efficiency (PCE) among the parallel photoanodes under visible light illumination (λ > 420 nm).

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Hydrogen (H2) has been deemed as the most promising and valuable alternative to nonrenewable fossil fuels. Photocatalytic and electrocatalytic water splitting are considered to be the most efficient and environmentally friendly approaches for the sustainable H2 evolution reaction (HER). Graphene with a 3D framework has been utilized for the HER due to its unique structure and properties, including its hierarchical network, large specific surface area, diverse pore distribution, outstanding light absorption ability, and excellent electrical conductivity. The large specific surface area and hierarchically porous structure of 3D graphene can not only maximize the exposure of active sites but also promote electron transfer and gas product diffusion. In addition, the free‐standing 3D graphene monolith is easily recycled compared with powder phase support, which can prevent the loss of active catalysts. By making full use of the aforementioned merits, 3D graphene‐based composite materials show great promise as high‐performance catalysts toward photocatalytic and electrocatalytic HER. In this review, recent advances in fabricating 3D graphene‐based composite materials and their applications in both photocatalytic and electrocatalytic HER are summarized and discussed. Furthermore, the current challenges and future vision associated with the design, fabrication, and integration of 3D graphene‐based composite materials toward HER are put forward.