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[Display omitted] Designing highly active and stable bifunctional catalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) under alkaline conditions is crucial for sustainable overall water splitting. Herein, we present a targeted reconstruction of Ni 3 S 2 by introducing tantalum, achieving remarkable overall water splitting performance through the separate activation of the lattice oxygen mechanism and hydrogen spillover. Electrochemical Mass Spectrometry and in-situ Raman spectroscopy reveal that tantalum induces Ni 3 S 2 to reconstruct into nickel hydroxide during OER, thereby enhancing catalytic activity via the activation of the lattice oxygen mechanism. In the corresponding HER, tantalum promotes the reconstruction of Ni 3 S 2 into oxysulfide, facilitates hydrogen spillover, and acts as an anchor to shorten the spillover distance, improving the HER catalytic performance, as verified by the kinetic isotope effect and theoretical calculations. Therefore, the catalyst-based anion exchange membrane water electrolyzer system achieves a current density of 1 A cm−2 at just 1.97 V, maintaining continuous operation for 500 h. This study offers new insights into the design of bifunctional catalysts, advancing the development of efficient and robust overall water splitting catalysts. [ABSTRACT FROM AUTHOR]

The substantial promotion of hydrogen evolution reaction (HER) catalytic performance relies on the breakup of the Sabatier principle, which can be achieved by the alternation of the support and electronic metal support interaction (EMSI) is noticed. Due to the utilization of tungsten disulfides as support for platinum (Pt@WS2), surprisingly, Pt@WS2 demands only 31 mV overpotential to attain 10 mA cm−2 in acidic HER test, corresponding to a 2.5‐fold higher mass activity than benchmarked Pt/C. The pH dependent electrochemical measurements associated with H2‐TPD and in situ Raman spectroscopy indicate a hydrogen spillover involved HER mechanism is confirmed. The WS2 support triggers a higher hydrogen binding strength for Pt leading to the increment in hydrogen concentration at Pt sites proved by upshifted d band center as well as lower Gibbs free energy of hydrogen, favourable for hydrogen spillover. Besides, the WS2 shows a comparably lower effect on Gibbs free energy for different Pt layers (−0.50 eV layer−1) than carbon black (−0.88 eV layer−1) contributing to a better Pt utilization. Also, the theoretical calculation suggests the hydrogen spillover occurs on the 3rd Pt layer in Pt@WS2; moreover, the energy barrier is lowered with increment in hydrogen coverage on Pt. Therefore, the boosted HER activity attributes to the EMSI effect caused hydrogen spillover and enhancement in Pt utilization efficiency. [ABSTRACT FROM AUTHOR]

Water electrolysis in alkaline media, demonstrating robust facility and cheap electrolyzer construction, are regarded as a promising strategy for industrial green hydrogen generation. Exploring effective alkaline hydrogen evolution electrocatalysts is remained an obstacle to date, which requires additional effort to obtain active hydrogen by water dissociation and promote the following unfavorable hydrogen coupling for further H2 release. Herein, the MoO2 supported RuNi nanoparticle (RuNi‐MoO2) is constructed as an efficient electrocatalyst for hydrogen evolution. Experimental and theoretical analysis demonstrate that the optimized built‐in electric field at the interface between MoO2 and RuNi alloy simultaneously accelerates the water dissociation kinetics and hydrogen spillover. It attains the current densities of 10 and 100 mA cm−2 at ultralow potential of −0.019 and −0.086 V versus RHE, respectively, along with rapid water cleavage kinetics, which even surpasses the commercial Pt/C. The constructing anion exchange membrane water electrolyzer adopting the RuNi‐MoO2 as a cathode electrocatalyst attains an industrial current density of 1 A cm−2 at a low voltage of 1.71 V and steadily operates over 1000 h with a large current density over 1 A cm−2. [ABSTRACT FROM AUTHOR]

Composite catalyst (CC) Ni/HMOR/ –ZrO2 is used to study the hydroconversion of benzene and toluene at atmospheric pressure, a temperature of 180°C, WHSV = 2 h−1, and Н2/ArH = 8. The conversion of benzene is as high as 58.2%. Adding an alkyl substituent raises conversion to 78.5%. It is shown that the primary conversion of toluene is similar to the conversion of benzene through selective aromatic ring hydrogenation with its subsequent isomerization, ring reduction, and hydrocleavage. Components of the catalytic system are inactive in the hydroconversion of aromatic hydrocarbons. Synergism emerges in the hydrogenating CC activity due to the cojoint effect which individual inactive –ZrO2 and Ni/HMOR components of this system have on the reaction. The probable mechanism of the hydrogenation of aromatic hydrocarbons is discussed. It is hypothesized that hydrogenating activity synergism results from the radical reaction becoming one of an ion radical. [ABSTRACT FROM AUTHOR]

Selective electrocatalytic hydrogenation (ECH) of phenol is a sustainable route to produce cyclohexanone, an industrially important feedstock for polymer synthesis. However, attaining high selectivity and faradaic efficiency (FE) for cyclohexanone remain challenging, owning to over‐hydrogenation of phenol to cyclohexanol and competition of hydrogen evolution reaction (HER). Herein, by employing hydrogen spillover effect, we modulate adsorbed hydrogen species (Hads) coverage on Pt surface via migration to TiO2 in an anatase TiO2‐supported Pt catalyst. In ECH of phenol, a high selectivity (94 %) and good FE (63 %) for cyclohexanone are obtained, showing more advantageous performance compared with previous reports. Cyclic voltammetry (CV) tests and electrochemical Raman spectroscopy reveal that Hads migrated from Pt to TiO2. We propose that TiO2‐induced hydrogen spillover contributes to low Hads coverage over Pt, which effectively hinders over‐hydrogenation of cyclohexanone and HER. We establish a scaling relationship between the intensity of hydrogen spillover and cyclohexanone selectivity by varying the types of anatase TiO2, and show the universality of the strategy over other reducible metal oxides as the support (rutile TiO2, CeO2 and WO3). This work showcases an effective strategy for tuning hydrogenation selectivity in electro‐catalysis, by taking advantage of thermo‐catalytically well‐documented hydrogen spillover effect. [ABSTRACT FROM AUTHOR]

The electrosynthesis of multi‐carbon (C2+) alcohols, specifically ethanol and n‐propanol through CO electroreduction (CORR) in H2O, presents a sustainable pathway for intermittent renewable energy storage and a low‐carbon economy. However, achieving high selectivity for alcohol production at industrial current densities is kinetically hampered by side reactions such as ethylene generation and hydrogen evolution reaction, which result from competing adsorption of *CO and *H. In this study, we developed a Cu/Zn alloy catalyst to simultaneously enhance the activity and selectivity for alcohol production by increasing CO capture capacity and enriching active hydrogen on Cu sites. Our findings demonstrate that the Cu/5Zn alloy with a molar ratio of Cu to Zn of 95 : 5 exhibits a Faradaic efficiency of 50 % for the selective electrosynthesis of C2+ alcohols during ampere‐level CO electrolysis. Mechanistic investigations revealed that the Cu/Zn alloy promotes polarized Cu sites, enhancing CO adsorption while facilitating the spillover of hydrogen atoms from Zn to Cu sites, contributing to selective alcohol formation. [ABSTRACT FROM AUTHOR]

Constructing nonmetal promoter‐decorated Pt‐based catalysts is a promising strategy for enhancing selective hydrogenation performance. In this study, a set of carbon dots (CDs)‐modified Pt/SBA‐15 nanocatalysts were synthesized using atomic layer deposition (ALD) and impregnation techniques. The catalysts were characterized using various techniques, including TEM, ICP‐MS, N2 adsorption–desorption isotherms, XRD, XPS, H2−TPD, H–D exchange, CO‐DRIFTS, and so forth. The catalytic performance of the CDs‐Pt/SBA‐15 catalysts was evaluated by the selective hydrogenation reaction of cinnamaldehyde (CAL) to cinnamyl alcohol (COL). The results indicate that there is electron transfer between the CDs and Pt, and the addition of CDs can improve the hydrogen spillover effect, both of which significantly influence the selective catalytic hydrogenation performance of the CDs‐Pt/SBA‐15 catalysts. Among the tested catalysts, 0.44CDs‐Pt/SBA‐15 demonstrated the highest catalytic performance, with conversion and selectivity 2.8 times and 2.2 times higher, respectively, than Pt/SBA‐15. This study provides a new perspective on designing and preparing highly efficient nonmetallic promoter‐modified Pt‐based nanocatalysts and has significant implications for their application in catalytic reactions. [ABSTRACT FROM AUTHOR]

In the pursuit of utilizing renewable energy sources for green hydrogen (H2) production, alkaline water electrolysis has emerged as a key technology. To improve the reaction rates of overall water electrolysis and simplify electrode manufacturing, development of bifunctional electrocatalysts is of great relevance. Herein, CoPBO/Co3O4 is reported as a binary composite catalyst comprising amorphous (CoPBO) and crystalline (Co3O4) phases as a high‐performing bifunctional electrocatalyst for alkaline water electrolysis. Owing to the peculiar properties of CoPBO and Co3O4, such as complementing Gibbs free energy values for H‐adsorption (ΔGH) and relatively smaller difference in their work functions (ΔΦ), the composite exhibits H2 spillover (HS) mechanism to facilitate the hydrogen evolution reaction (HER). The outcome is manifested in the form of a low HER overpotential of 65 mV (at 10 mA cm−2). Moreover, an abundant amount of surface oxygen vacancies (Ov) are observed in the same CoPBO/Co3O4 composite that facilitates oxygen evolution reaction (OER) as well, leading to a mere 270 mV OER overpotential (at 10 mA cm−2). The present work showcases the possibilities to strategically design non‐noble composite catalysts that combine the advantages of HS phenomenon as well as Ov to achieve new record performances in alkaline water electrolysis. [ABSTRACT FROM AUTHOR]

Developing efficient electrocatalyst in sulfides for hydrogen evolution reaction (HER) still poses challenges due to the lack of understanding the role of sulfide heterointerface. Here, we report a sulfide heterostructure RuSx/NbS2, which is composed of 3R‐type NbS2 loaded by amorphous RuSx nanoparticles with S−S bonds formed at the interface. As HER electrocatalyst, the RuSx/NbS2 shows remarkable low overpotential of 38 mV to drive a current density of 10 mA cm−2 in acid, and also low Tafel slope of 51.05 mV dec−1. The intrinsic activity of RuSx/NbS2 is much higher than that of Ru/NbS2 reference as well as the commercial Pt/C. Both experiments and theoretical calculations unveil a reversed charge transfer at the interface from NbS2 to RuSx that driven by the formation of S−S bonds, resulting in electron‐rich Ru configuration for strong hydrogen adsorption. Meanwhile, electronic redistribution induced by the sulfide heterostructure facilitates hydrogen spillover (HSo) effect in this system, leading to accelerated hydrogen desorption at the basal plane of NbS2. This study provides an effective S−S bond strategy in sulfide heterostructure to synergistically modulate the charge transfer and adsorption thermodynamics, which is very valuable for the development of efficient electrocatalysts in practical applications. [ABSTRACT FROM AUTHOR]

Alkaline water splitting has shown great potential for industrial‐scale hydrogen production. However, its broad application is constrained by hydrogen evolution reaction (HER) electrocatalysts, which struggle to achieve optimal current density at low overpotential. The utilization of the hydrogen spillover effect to augment the performance of HER represents a burgeoning area of research. Although previous studies mainly focused on hydrogen spillover in acidic media, the latest studies have shown that hydrogen spillover also exists under alkaline conditions, and its role in improving HER performance cannot be ignored. This review examines the mechanisms of HER under acidic and alkaline conditions, elucidating the distinctive behavior of hydrogen spillover in these environments and its influence on catalytic processes. At the same time hydrogen spillover characterization methods are systematically summarized, these technologies for understanding and control of hydrogen release process provides strong support. Finally, the recent electrocatalysts that enhance the catalytic performance of alkaline HER by hydrogen spillover effect are comprehensively sorted out and summarized. This review not only demonstrate the practical value of hydrogen spillover under alkaline conditions, but also provide new directions for future design and optimization of electrocatalysts. [ABSTRACT FROM AUTHOR]

The reverse water‐gas shift (RWGS) reaction serves as a critical pathway for converting CO2 into diverse chemicals. The Mars–van Krevelen (MvK) mechanism, which leverages lattice oxygen as the oxidant and oxygen vacancies as reductants, offers an alternative catalytic strategy for the selective RWGS reaction. While Mn‐substituted SrTiO3 (i. e., SrTi0.8Mn0.2O3) has been shown to promote the RWGS reaction selectively via the MvK mechanism, achieving a sufficient conversion of CO2 necessitates elevated temperatures. This study investigated the effect of Pd‐loaded SrTi0.8Mn0.2O3 on the activation of adsorbed H2 molecules, which generated oxygen vacancies and enhanced CO2 conversion. Notably, 1.0 wt % Pd‐loaded SrTi0.8Mn0.2O3 yielded 13.4 % of CO at 673 K, whereas pristine SrTi0.8Mn0.2O3 and Pd‐loaded SrTiO3 yielded negligible or minimal amount of CO. Hydrogen temperature‐programmed reduction and X‐ray absorption spectroscopy measurements revealed that Pd promoted the formation of oxygen vacancies via both thermodynamic and kinetic mechanisms. Fourier transform infrared spectroscopy and kinetic studies revealed that the RWGS reaction over Pd‐loaded SrTi0.8Mn0.2O3 proceeded primarily via the MvK mechanism with a partial contribution from the Langmuir–Hinshelwood mechanism. This study underscores the effectiveness of combining metal and MvK‐type catalysts to enhance the efficiency of the RWGS reaction. [ABSTRACT FROM AUTHOR]

Membrane‐based gas separation offers notable energy efficiency benefits for hydrogen purification, yet it is often hindered by the inherent trade‐off between permeability and selectivity. To address this challenge, a novel mixed matrix membrane (MMM) design is presented to boost H2 separation performance via continuous hydrogen spillover mechanisms for the first time. The MMM incorporates a palladium‐functionalized ZIF‐67 gel (Pd@ZIF‐67 gel) network into a polymer of intrinsic microporosity (PIM‐1) matrix. The ZIF‐67 gel network serves as a uniform dispersion medium for palladium nanoparticles (Pd NPs), thereby generating a multitude of active sites. These exposed sites, in conjunction with the microporous structure of ZIF‐67, facilitate hydrogen dissociation and establish a continuous hydrogen spillover pathway throughout the membrane. This synergistic MMM design leads to substantial improvements in both hydrogen transport and selectivity. At an optimal loading of 28 wt% Pd@ZIF‐67 gel, the MMMs exhibit a H2 permeability of 3620 Barrer and a remarkable 417% enhancement in H2/CH4 selectivity (24.9), surpassing the 2008 upper bound. This approach paves the way for the development of advanced materials tailored for gas separation applications. [ABSTRACT FROM AUTHOR]

The conversion of CO2 into formate through electrochemical methods is emerging as an elegant approach for industrial‐scale CO2 utilization in the near future. Although Bismuth (Bi)‐based materials have shown promise thank to their excellent selectivity, their limited reactivity remains a challenge. Herein, this study demonstrates a significant enhancement in the CO2‐to‐formate efficiency of Bi by incorporating ruthenium (Ru) atomic species. Ru single atom doped Bi exhibited a nearly twofold higher partial current density compared with pure Bi and Ru clusters doped Bi, while over 95% Faradaic efficiency (FE) is maintained. Through comprehensive investigations using a combined approach of electrochemical techniques, operando spectroscopy, and theoretical calculations, this study elucidates that the presence of Ru single atom promotes H2O dissociation and H* migration to Bi sites for CO2‐to‐formate conversion by significantly reducing the energy barrier via a H* spillover path. Besides, it is constructed Ru–Bi bridge sites for efficient CO2 hydrogenation via a non‐spillover path, which served as the major mechanism for CO2‐to‐formate conversion in Ru single atom doped Bi. [ABSTRACT FROM AUTHOR]

Herein, a heterogeneous structure of Ni–Mo catalyst comprising Ni4Mo nanoalloys decorated on a MoOx matrix via electrodeposition is introduced. This catalyst exhibits remarkable hydrogen evolution reaction (HER) activity across a range of pH conditions. The heterogeneous Ni–Mo catalyst showed low overpotentials only of 24 and 86, 21 and 60, and 37 and 168 mV to produce a current density of 10 and 100 mA cm−2 (η10 and η100) in alkaline, acidic, and neutral media, respectively, which represents one of the most active catalysts for the HER. The enhanced activity is attributed to the hydrogen spillover effect, where hydrogen atoms migrate between the Ni4Mo alloys and the MoOx matrix, forming hydrogen molybdenum bronze as additional active sites. Additionally, the Ni4Mo facilitated the water dissociation process, which helps the Volmer step in the alkaline/neutral HER. Through electrochemical analysis, in situ Raman spectroscopy, and density functional theory calculations, the fast HER mechanism is elucidated. [ABSTRACT FROM AUTHOR]

The development of efficient and durable bifunctional electrocatalysts is essential for hydrogen production from acidic water splitting. Herein, a TiO2 nanotube‐loaded Co‐doped Ru nanoparticle catalyst (RuCo/TiO2 NTs) is reported that exhibits excellent activity and stability toward acidic oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The Ru─O─Ti bonding is enhanced by Co doping, and the metal carrier interaction between Ru nanoparticles and TiO2 NTs is enhanced, which effectively stabilizes Ru species during OER and initiates hydrogen spillover accelerating HER kinetics. As a result, RuCo/TiO2 NTs catalyst requires only 156 mV OER overpotential and 17 mV HER overpotential to achieve a current density of 10 mA cm−2 with a stability more than 500 h in acidic conditions. More importantly, benefiting from the excellent bifunctional activities, the proton exchange membrane electrolyte assembled from RuCo/TiO2 NTs has excellent activity and robust stability (1000 h). This work opens a new avenue for the efficient energy conversion devices. [ABSTRACT FROM AUTHOR]

The hydrogen spillover mechanism of metal‐supported electrocatalyst can significantly improve HER activity. However, the rational design of binary heterojunction hydrogen spillover electrocatalysts remains a challenge. Here, a NiSe2‐Ni5P4 heterojunction electrocatalyst with superaerophobic structure is synthesized by using a simple substrate self‐derived strategy. Experimental characterization and theoretical calculation reveal the hydrogen spillover mechanism of NiSe2‐Ni5P4 heterogeneous electrocatalyst. NiSe2 and Ni5P4 synergistically promote the adsorption/dissociation of H2O and the adsorption of H*, respectively. The smaller ΔΦ effectively reduced the electron density at the interface, weakening the proton adsorption at the interface and promoting the migration of H* from NiSe2 to Ni5P4. The NiSe2‐Ni5P4 exhibits excellent HER activity in alkaline electrolyte, requiring only a potential of 65, 270 mV to achieve a current density of 10, 500 mA cm−2, respectively, and a stability of up to 200 h. Moreover, the design of NiSe2‐Ni5P4 with superaerophobic structure can reduce the deposition of impurity ions on the electrode surface and avoid Cl− corrosion of the electrode, which results in NiSe2‐Ni5P4 showing better HER activity and stability than commercial Pt/C in brackish water. This study deepens the understanding of hydrogen spillover mechanism of binary heterojunction electrocatalysts, broadens the application of hydrogen production in complex water quality. [ABSTRACT FROM AUTHOR]

[Display omitted] • A unique W-doped NiS x /Ni@Cu heterointerface was developed by electrodeposition. • W-doped NiS x /Ni heterointerface can lower the HER kinetic barrier. • The W-NiS x /Ni@Cu exhibits an attractive HER activity with a low overpotential of 38 mV at 10 mA cm−2. • The DFT calculations reveal the enhanced water dissociation and H intermediate desorption. Promoting water dissociation and H intermediate desorption play a pivotal role in achieving highly efficient hydrogen evolution reaction (HER) in alkaline media but remain a great challenge. Herein, we rationally develop a unique W-doped NiS x /Ni heterointerface as a favorable HER electrocatalyst which was directly grown on the Cu nanowire foam substrate (W-NiS x /Ni@Cu) by the electrodeposition strategy. Benefiting from the rational design of the interfaces, the electronic coupling of the W-NiS x /Ni@Cu can be efficiently modulated to lower the HER kinetic barrier. The obtained W-NiS x /Ni@Cu exhibits an enhanced HER activity with a low overpotential of 38 mV at 10 mA cm−2 and a small Tafel value of 27.5 mV dec−1, and high stability during HER catalysis. In addition, in-situ Raman spectra reveal that the Ni2+ active sites preferentially adsorb OH intermediate. The theoretical calculation confirms that the water dissociation is accelerated by the construction of W-NiS x /Ni heterointerface and H intermediate desorption can be also promoted by H spillover from S active sites in W-NiS x to Ni active sites in metal Ni. This work offers a valuable reference for rational designing heterointerface of electrocatalysts and provides an available method to accelerate the HER kinetics for the ampere-level current density under low overpotential. [ABSTRACT FROM AUTHOR]

Hydrogen spillover in metal‐supported catalysts can largely enhance electrocatalytic hydrogenation performance and reduce energy consumption. However, its fundamental mechanism, especially at the metal–metal interface, remains further explored, impeding relevant catalyst design. Here, we theoretically profile that a large free energy difference in hydrogen adsorption on two different metals (|ΔGH‐metal(i)−ΔGH‐metal(ii)|) induces a high kinetic barrier to hydrogen spillover between the metals. Minimizing the difference in their d‐band centers (Δϵd) should reduce |ΔGH‐metal(i)−ΔGH‐metal(ii)|, lowering the kinetic barrier to hydrogen spillover for improved electrocatalytic hydrogenation. We demonstrated this concept using copper‐supported ruthenium–platinum alloys with the smallest Δϵd, which delivered record high electrocatalytic nitrate hydrogenation performance, with ammonia production rate of 3.45±0.12 mmol h−1 cm−2 and Faraday efficiency of 99.8±0.2 %, at low energy consumption of 21.4 kWh kgamm−1. Using these catalysts, we further achieve continuous ammonia and formic acid production with a record high‐profit space. [ABSTRACT FROM AUTHOR]

Developing an efficient strategy to replace the conventional synthesis method for producing isoindolinone (IIO) scaffold, a crucial structural motif for constructing pharmaceutical molecules, remains to be a great challenge. Herein, a single‐atom Pd/TiO2 tandem catalysis has been developed for the IIO scaffold synthesis by using readily available phthalic anhydride (PA), ammonia, and H2. The single‐atom Pd/TiO2 catalyst demonstrates superior catalytic performance, achieving a PA conversion of 99 %, an IIO selectivity of 91 %, and a turnover frequency (TOF) up to 4807 h−1. This exceptional performance can be attributed to the tandem catalysis between TiO2 support and single‐atom Pd. The TiO2 efficiently catalyzes the conversion of PA with ammonia to form phthalimide (PAM), subsequently transformed into IIO over TiO2 through the reaction of PAM with NH3 and the spillover hydrogen species derived from single‐atom Pd. Notably, NH3 functions not only as a reactant but also as a promoter to accelerate the reduction of amides combined with the Pd/TiO2 catalyst. This tandem catalysis of a single‐atom Pd/TiO2 catalyst provides a promising strategy for the synthesis of the crucial IIO platform molecules. [ABSTRACT FROM AUTHOR]

Pt automatically adsorbed on oxygen vacancy of TiO2 via an in situ interfacial redox reaction, resulting in atomically dispersion of Pt on TiO2. In the upgrading of lignin‐derived 4‐propylguaiacol, single‐atom catalyst (SAC) Pt/TiO2−H achieved a conversion of 96.9 % and a demethoxylation selectivity of 93.3 % under 3 MPa H2 at 250 °C for 3 h, markedly different from the performance of nanoparticle counterpart that gave deep deoxygenation selectivity over 99.0 %. The high demethoxylation activity of SAC Pt/TiO2−H is mainly attributed to its weak hydrogen spillover capacity that suppressed the benzene ring hydrogenation and the deep deoxygenation. Additionally, SAC Pt/TiO2−H reduced the energy barrier of CAr−OCH3 bond cleavage and accordingly lowered the Gibbs free energy of the demethoxylation reaction. This facile method could fabricate single‐atom Au, Pd, Ir, and Ru supported on TiO2−H, demonstrating the generality of this strategy for the establishment of a library of SACs. Moreover, SAC exhibited versatile capacity in demethoxylation of different lignin‐derived monomers and high stability. This study showcases the superiority of atomically dispersed metal catalysts for selective demethoxylation reactions and proposes a renewable alternative to fossil‐based 4‐alkylphenols through upgrading of lignin‐derived monomers. [ABSTRACT FROM AUTHOR]

Interparticle hydrogen spillover is the phenomenon of H migration over different catalyst particles, which should be a physical mixture of at least two solid catalysts. In this review, we analyze examples of enhanced catalysis based on interparticle (reverse) hydrogen spillover. Simple physical mixtures of powdered catalysts containing metal catalysts of H2 dissociation/recombination and solid catalysts with active sites for substrate activation significantly enhance catalytic reactions. These reactions include aromatic hydrogenation, CO2 methanation, and the deoxydehydration of polyols, aromatization of lower paraffins, and direct coupling of benzene and alkanes. The acceleration effect and proposed reaction pathway of each example involving interparticle (reverse) hydrogen spillover are summarized. Simple reaction systems comprising physical mixtures of at least two powdery solid catalysts should enable unique catalysis in the future with the aid of interparticle (reverse) hydrogen spillover. [ABSTRACT FROM AUTHOR]

The effectuation of pH‐universal electrocatalysis is highly attractive but still challenging for the hydrogen evolution reaction (HER). It appeals for not only the facilitated electron transport but also the kinetical proton mass transfer. In this study, a via‐hole Ru/MoO2 confined heterostructure is profiled as a metal‐support platform for the electron/mass transfer‐boosted pH‐universal HER studies. It is indicated that the as‐formed Ru─O─Mo bridge can modulate the electronic transport at the interface, and the proton adsorption and transfer are kinetically derived by the intensified metallic Ru─Ru bond. Resultantly, the Ru/MoO2 heterostructure stably attains the Pt‐beyond HER activity with an ultralow overpotential of 9.2 mV at 10 mA cm−2 in 1 m KOH, and also achieves the competitive HER activity and stability in the acidic/neutral electrolytes. Both the experimental and computational results reveal the accelerated HER kinetics is attributable to the intensive mass transfer through the interfacial Ru→MoO2 hydrogen spillover effect. This work opens up the opportunities to rationalize the advanced metal‐support HER electrocatalysts through the interfacial hydrogen spillover effect and metallic bond engineering. [ABSTRACT FROM AUTHOR]

Graphene-based nanostructures loaded with transitional metallic atoms have been identified as promising materials for hydrogen storage. In this study, we investigate the adsorption and spillover of hydrogen on a single transitional metal atom incorporated graphene (TM-Gr) through density functional theory (DFT) calculations. Specifically, we explore the geometric and electronic properties of 20 different TM-Gr structures. Our findings reveal that Y-Gr and Sc-Gr exhibit the most favorable H atom adsorption, while Mn-Gr and Cr-Gr are more suitable for H spillover. Additionally, feature importance analysis highlights that Bader charge accumulated in H atom, C-H bond length, and work function of TM-Gr are the three most important features that are sensitive to the activation energy of H spillover. Overall, this work provides valuable insights for the screening of new materials for hydrogen storage. [ABSTRACT FROM AUTHOR]

Hydrogen storage technology is a critical segment for solving future energy problems and is currently an escalating issue for developing our energy economy. In the past two decades, numerous theoretical works and hydrogen storage experiments have been carried out to explore hydrogen storage through the hydrogen spillover method. Hydrogen spillover was found to be an effective method to improve the hydrogen storage performance of carbon – based materials at room temperature. This review mainly addressed the principles of hydrogen spillover, evidence for improving hydrogen storage efficiency, and theoretical studies on the spillover method. In an effort to find some ideas on which materials could be used to store hydrogen at room temperature, we summarized the influencing components of spillover for hydrogen storage from three perspectives: hydrogen storage materials, efficient catalysts, and other factors. Finally, we outlined the current problems and future research directions for hydrogen storage at room temperature and proposed some strategies to address them. [ABSTRACT FROM AUTHOR]

Employing the alkaline water electrolysis system to generate hydrogen holds great prospects but still poses significant challenges, particularly for the construction of hydrogen evolution reaction (HER) catalysts operating at ampere-level current density. Herein, the unique Ru and RuP2 dual nano-islands are deliberately implanted on N-doped carbon substrate (denoted as Ru-RuP2/NC), in which a built-in electric field (BEF) is spontaneously generated between Ru-RuP2 dual nano-islands driven by their work function difference. Experimental and theoretical results unveil that such constructed BEF could serve as the driving force for triggering fast hydrogen spillover process on bridged Ru-RuP2 dual nano-islands, which could invalidate the inhibitory effect of high hydrogen coverage at ampere-level current density, and synchronously speed up the water dissociation on Ru nano-islands and hydrogen adsorption/desorption on RuP2 nano-islands through hydrogen spillover process. As a result, the Ru-RuP2/NC affords an ultra-low overpotential of 218 mV to achieve 1.0 A·cm−2 along with the superior stability over 1000 h, holding the great promising prospect in practical applications at ampere-level current density. More importantly, this work is the first to advance the scientific understanding of the relationship between the constructed BEF and hydrogen spillover process, which could be enlightening for the rational design of the cost-effective alkaline HER catalysts at ampere-level current density. [ABSTRACT FROM AUTHOR]

Highlights Pt–Ni bonded Pt single-atom (SA) catalyst, rather than classic Pt–O bonded SA catalyst, was successfully constructed. The electronic states of Pt SA catalyst were deeply regulated and negatively charged Pt δ− was realized. Pt–Ni bonded Pt SA catalyst-enhanced absorbability for activated hydrogen atoms and promoted hydrogen absorption.

Highlights: Pt–Ni bonded Pt single-atom (SA) catalyst, rather than classic Pt–O bonded SA catalyst, was successfully constructed. The electronic states of Pt SA catalyst were deeply regulated and negatively charged Ptδ− was realized. Pt–Ni bonded Pt SA catalyst-enhanced absorbability for activated hydrogen atoms and promoted hydrogen absorption. Single-atom (SA) catalysts with nearly 100% atom utilization have been widely employed in electrolysis for decades, due to the outperforming catalytic activity and selectivity. However, most of the reported SA catalysts are fixed through the strong bonding between the dispersed single metallic atoms with nonmetallic atoms of the substrates, which greatly limits the controllable regulation of electrocatalytic activity of SA catalysts. In this work, Pt–Ni bonded Pt SA catalyst with adjustable electronic states was successfully constructed through a controllable electrochemical reduction on the coordination unsaturated amorphous Ni(OH)2 nanosheet arrays. Based on the X-ray absorption fine structure analysis and first-principles calculations, Pt SA was bonded with Ni sites of amorphous Ni(OH)2, rather than conventional O sites, resulting in negatively charged Ptδ−. In situ Raman spectroscopy revealed that the changed configuration and electronic states greatly enhanced absorbability for activated hydrogen atoms, which were the essential intermediate for alkaline hydrogen evolution reaction. The hydrogen spillover process was revealed from amorphous Ni(OH)2 that effectively cleave the H–O–H bond of H2O and produce H atom to the Pt SA sites, leading to a low overpotential of 48 mV in alkaline electrolyte at −1000 mA cm−2 mg−1Pt, evidently better than commercial Pt/C catalysts. This work provided new strategy for the controllable modulation of the local structure of SA catalysts and the systematic regulation of the electronic states. [ABSTRACT FROM AUTHOR]