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[Display omitted] • Atomic doping combine surface ion graft is first time used to boost photocatalytic. • Atomic doping effect is systematically studied for the optimal heteroatomic doping. • Atom doping and surface ion graft synergistically manipulate photocharges separation. The synergistic implementation of atomic-level charge separation strategies for bulk–surfaces is a meaningful study that fundamentally addresses the shortcomings of single materials. Here, we report for the first time the atomic-level engineering of atomic doping in combination with surface ion grafting, which can be coordinated to significantly facilitate photocatalytic H 2 evolution. More impressively, the study systematically investigated the atomic doping effects of Fe, Co, Ni and Cu atoms, and analyzed the conditions for optimal doping with experimental and theoretical calculations. The doping of variable valence Cu atoms leads to the emergence of newly occupied electronic states at the Fermi energy level, which effectively improves the carrier separation. The X-ray absorption spectroscopy (XAS) results verified the precise coordination environments of the doped Cu atoms, as well as confirmed the solid grafting of Ni ions on the catalyst surface. Furthermore, the hydrogen production rate of 1.2 % Cu–Zn 0.67 Cd 0.33 S–0.5 wt% Ni reached 38.17 mmol/g/h, corresponding to an apparent quantum efficiency of 35.5 %, which is 82.8 times higher than that of pure ZCS. Besides, the H 2 production rate can reached 118.73 mmol/g/h without cooling. Meanwhile, the synergistic strategy of manipulating the bulk and surface photo-charges of Zn 0.67 Cd 0.33 S also effectively enhances the photothermal effect and further improves its photocatalytic performance. This work provides different inspirations for bottom-up design of efficient photocatalysts to achieve synergistic facilitation strategies. [ABSTRACT FROM AUTHOR]

[Display omitted] • W-NiCo 2 O 4 -2 hierarchical porous sheets facilitate mass transport. • W6+ doping optimizes the adsorption of oxygen intermediates. • The optimized electron structure promotes the formation of MOOH (M = Co, W). • W6+ doping enhances the intrinsic conductivity of NiCo 2 O 4. Limited specific surface area, active site amount, and intrinsic conductivity inhibit spinels' electrocatalytic oxygen evolution reaction (OER) activity. Herein, we proposed a high-valence oxyanion exchange strategy for preparing hierarchical sheet-like W-NiCo 2 O 4 -2 spinel OER electrocatalyst, which exhibits favorable activity (306 mV overpotential@10 mA cm−2) and durability in 1.0 M KOH solution, and shows an application prospect in a home-made anion exchange membrane (AEM) electrolyzer. BET results showed that the hierarchical structure increased specific surface area and corresponding edge active sites amount, accelerated mass transport and charge transfer. XPS, ex-situ Raman spectroscopy, and HRTEM characterizations dispicted that W6+ doping optimizes e g orbital electron filling and promotes M−OOH (M = Co, W) active species generation. DFT calculations reveal that W6+ doping modulates the adsorption of oxygen intermediates, improving the reaction kinetics, and increasing the density of electronic states nearby the Fermi level, thus enhancing conductivity. This work provides a universal pathway for modulating spinel-based OER electrocatalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • Homo double Ru 2 /Mo 2 CO 2 was derived via activity, stability, and selectivity screening. • Elucidating the correlation between the d-band structure of metal cation constituting the MXene support and the electron density near the Fermi level of single and homo double atom catalyst. • The change in the activity of single and double atoms supported on the MXene surface originated from the difference in overlap ratio between their d orbital and the p orbital of the N atom in NH 2 adsorbate. In this study, we have engineered the MXene supports to boost the single and homo double atoms of Fe, Ru, and Os for efficient NH 3 production via electrochemical nitrogen reduction reaction (N 2 RR) using DFT calculations. We designed the different MXene surfaces which are composed of nine early transition metals [M 2 CO 2 (M = Cr, Hf, Mo, Nb, Ta, Ti, V, W, Zr)] and examined the activity/stability of single and homo double atoms by calculating the free energy diagram of N 2 RR, dissolution potential, and agglomeration energy. First, we found that the NH 2 adsorption energy is the activity descriptor for representing the NH 3 productivity and the density of state near the Fermi level of the single Ru atom is the important factor in determining N 2 RR activity. Next, our DFT calculation on the descriptor-based computational search for the novel MXene-based catalysts showed that among the chemically and electrochemically stable candidate catalysts, the homo double Ru 2 /Mo 2 CO 2 catalyst showed the highest NH 3 productivity with the high N 2 RR selectivity over hydrogen evolution reaction. In addition, the best Ru 2 /Mo 2 CO 2 catalyst exhibited the intermediate density of state near the Fermi level, leading to the optimal descriptor value (NH 2 adsorption strength) for NH 3 production and in turn the reduction of overpotential for the electrochemical NH 3 production. More fundamentally, we identified that the electron density near the Fermi level of these single or double atoms is closely correlated with the electron structure of the cationic metal atoms constituting MXene supports. Our study highlights the rational design of single and homo double atom catalysts by tuning the property of MXene supports, which provides insight into the key factors in enhancing NH 3 production at ambient conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • The difference in Fermi level between Ru and M x O y results in electron transfer. • The BEF created by the charge transfer facilitates the transfer of the charge. • The electronic structure of Ru was regulated by M x O y. • The interaction between Ru and M x O y improves the stability and activity of Ru. • The porous structure of the catalysts promotes the diffusion of electrolyte. The differences in Fermi levels (E f) can drive the electrons flow across the metal/semiconductor interfaces, resulting in a built-in electric field (BEF) to enhance charge migration. Meanwhile, the induced electron-rich/deficient counterparts can modulate the active sites and reaction steps. In this work, a three-dimensionally ordered macroporous (3DOM) heterostructure with oxygen vacancy (O v) supported by carbon (Ru/M x O y @C, M = V, Nb, Ta) was fabricated. Since the E f of M x O y is higher than that of Ru, an adjustable BEF directed by M x O y towards Ru is generated at the interface. The electron-deficient M x O y can dissociate H 2 O effectively, and the electron-rich Ru favors the desorption of hydrogen intermediates. Both experimental and theoretical results confirm the above conclusions. The Ru/Ta 2 O 5 @C demonstrates superior activity than Pt/C. This work provides new design principles toward efficient electrocatalysts for hydrogen evolution reaction (HER). [ABSTRACT FROM AUTHOR]

The metal–metal oxide-support interaction stabilized MoO 4 2- is realized in a mesoporous carbon supported heterogenous Ni 4 Mo/NiMoO 4 structure (NiMoO x @CMK-3) for boosting hydrogen evolution. [Display omitted] • A novel NiMoO x @CMK-3 electrocatalyst is synthesized for promoted HER process and outstanding AEMWE performance. • The ex/in-situ characterization evidence the strong heterointerface inhibits the MoO 4 2- loss. • DFT calculations reveal the optimized heterogeneous NiMoO x possesses a moderate Mo-H* binding energy for HER. Constructing low-cost, high-active and robust heterogeneous hydrogen evolution reaction (HER) electrocatalysts with strong metal–metal oxide-support interaction (SMMOSI) is still an urgent challenge for the development of anion exchange membrane water electrolysis (AEMWE), especially under high current density (e.g., 1 A cm−2). Herein, a hierarchical composite of heterogenous Ni 4 Mo/NiMoO 4 (NiMoO x) nanoparticles (NPs) anchored on a mesoporous carbon CMK-3 (NiMoO x @CMK-3) is designed as a superior electrocatalyst for HER. Significantly, the strong interaction between heterogeneous NiMoO x NPs and CMK-3 supporting matrix effectively stabilize the catalytic active Ni 4 Mo/NiMoO 4 heterostructure by altering the local geometric and electronic structures, leading to maximumly exposure of active sites and promoted electron transfer ability. The optimized electrocatalyst exhibits outstanding HER activity with an extremely low overpotential and Tafel slope of 7 mV@10 mA cm−2 and 27.7 mV dec-1, respectively, and can steadily operate at 100 mA cm−2 for 800 h. More significantly, owing to these HER merits, the AEMWE configuration with NiMoO x @CMK-3 (−) is also designed, resulting in low cell voltage of 1.965 V@1 A cm−2 and negligible degradation over 400 h@1 A cm−2. Further ex/in-situ electrochemical spectra evidence that both the partial combined MoO 4 2- from NiMoO 4 and the newly formed MoO 4 2- originating from dissolved Mo in NiMoO x @CMK-3 could boost the fast generation of polymerized Mo 2 O 7 2- that could effectively accelerate the HER process in alkaline conditions by facilitating the formation of active Mo-H* intermediates. Moreover, theoretical calculation results demonstrate the upshifting of d-band center of Mo toward Fermi level for the heterogeneous NiMoO x and the strong charge distribution between the heterointerface could optimize adsorption free energies of H* (ΔG H*) on the surface of Mo atoms. [ABSTRACT FROM AUTHOR]

[Display omitted] • N and O co-coordination of Fe single atom is realized by pre-oxidation strategy. • The coordination of axial O to Fe optimizes the adsorption energy of oxygen species. • This work reveals that Fe nanoparticles can induce more Fe single atoms to de-anchor. • SA-FeN 4 O 1 -C catalyst shows excellent performance in GDE half-cell and ZABs. Single-atom catalysts have recently emerged as a promising replacement for noble metal catalysts in the oxygen reduction reaction (ORR) on the cathode side of fuel cells and metal-air batteries. However, regulating the precise coordination environment of central atoms remains challenging. In particular, constructing co-coordination active site with N and O atom is rarely investigated. Here, an unreported pre-oxidation strategy is proposed to establish the Fe-O bond for the synthesis of the Fe-N 4 O 1 single-atom structure. The obtained SA-FeN 4 O 1 -C catalyst exhibits remarkable ORR performance, possessing a half-wave potential 30 mV higher than that of the commercial Pt/C and a kinetic current density 7.4 times that of Pt/C at 0.8 V (vs. RHE). More significantly, when employed as an air cathode, the overpotential is 340 mV lower than that of Pt/C when operating at a high current density of 350 mA cm−2 in a GDE half-cell, and a maximum power density of 205.8 mW cm−2 and a high energy density of 1024.9 w h kg−1 can be achieved in a zinc-air battery. According to the DFT, axial oxygen coordination can lower the energy barrier for ORR by driving the d-band center of the Fe atom to shift away from the Fermi level and generate a moderate oxygen adsorption energy. Importantly, the essence of the formation of the Fe-N 4 O 1 structure and single-atomic active sites was revealed. This work opens up an innovative strategy for constructing single-atom sites with axial oxygen coordination and provides valuable insight into the synthesis of atomically dispersed materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • {1 2 ¯ 3} faceted NiWO 4 -Ni 3 S 2 @NiO/NF electrodes with tunable S vacancies were devised. • The facets and S vacancies on Ni 3 S 2 determined the overpotential (η) and TOF in HER. • A η 10 of 89 mV and a TOF of 1.5 × 10−3 s−1 were attained on NiWO 4 -Ni 3 S 2 @NiO/NF-3. • DFT calculations revealed the manipulation mechanism of facets and S vacancies. • An overall-water-splitting current density of 10 mA cm−2 at 1.64 V was achieved. Designing nonprecious electrocatalysts with outstanding performances in hydrogen evolution reaction (HER) via water splitting is attractive for renewable energy conversion. Here, a free-standing and binder-free electrode by in-situ growing a multi-level layered electrocatalyst consisted of NiWO 4 -coupled Ni 3 S 2 nanofibers with secondary NiO layer on Ni foam (NiWO 4 -Ni 3 S 2 @NiO/NF) is devised, in which NiWO 4 was recognized to boost the exposure of high-index {1 2 ¯ 3} facets on Ni 3 S 2 and NiO was identified to increase the electron density of Ni 3 S 2 via accumulating S vacancies. Such an integration of high‑index‑facet exposure and electron-density optimization endowed the resultant NiWO 4 -Ni 3 S 2 @NiO/NF-3 (3 represents the nominal Ni: S molar ratio in fabricating Ni 3 S 2) electrode with a more suitable H adsorption energy on the active Ni sites and a positive shift of the d-band center of Ni 3 S 2 toward the Fermi level, resulting in a strengthened Ni–H interaction. As a consequence, a low overpotential of 89 mV to deliver a current density of 10 mA cm−2 and a high turnover frequency of H 2 generation of 1.5 × 10−3 s−1 for HER in 1 mol l−1 KOH were acquired on NiWO 4 -Ni 3 S 2 @NiO/NF-3, both outperforming the Ni 3 S 2 /NF-1, NiWO 4 -Ni 3 S 2 /NF-1, and NiWO 4 -Ni 3 S 2 @NiO/NF-1 electrocatalysts. Remarkably, an electrolytic cell assembled by using NiWO 4 -Ni 3 S 2 @NiO/NF-3 as both anode and cathode delivered an overall-water-splitting current density of 10 mA cm−2 at 1.64 V, evidencing its robust bifunctional catalytic ability in water splitting. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Pd-B/C with the control of inserted-B atoms are synthesized by a facile route. • The optimized Pd-B/C catalyst exhibit superior alkaline HER activity. • The inserted boron atoms is beneficial to regulate the intermediate affinity on Pd. Strong affinity of palladium to hydrogen needs to be overcome in the rational design of highly efficient and robust Pd-based catalyst for hydrogen evolution reaction (HER). In this work, we achieved the insertion of boron atoms in the Pd lattice interstitial sites by a facile co-reduction method, and successfully prepared Pd-B nanoparticles supported on carbon. Benefiting from the optimization of electronic state induced by the control of interstitial boron atoms, the obtained Pd 86 B 14 /C catalyst exhibit pronounced alkaline HER performance with a small overpotential of 38 mV at 10 mA cm−2 and a low Tafel slope of 36.6 mV dec−1 in 1 M KOH. Theoretical calculations unveil that the inserted boron atoms into host palladium leads to the charge redistribution and the lower d-band center on Pd because of the electron transfer between Pd and inserted B. More importantly, the control of inserted boron atoms makes the d-band center of Pd appropriately shift negatively relative to the Fermi level and consequently balances the hydrogen adsorption/desorption behavior of Pd surface, resulting in superior catalytic performance (Pd 86 B 14 /C). [ABSTRACT FROM AUTHOR]

[Display omitted] • Successfully in-situ grown 3D "Celosia" porous heterostructures on MXene/NF. • A simple and effective synthesis route by the one-pot hydrothermal method. • Efficacious electronic tuning engineering for this heterogeneous interface. • An optimized reaction intermediate adsorption energy calculated by DFT. • The catalyst exhibits excellent electrocatalytic overall water splitting performance. Exploiting efficient and economical electrocatalysts is indispensable for promoting the sluggish kinetics of overall water-splitting. Herein, we ingeniously designed a simple one-pot hydrothermal method to construct a 3D porous "celosia-like" heterogeneous framework of FeCo-layered double hydroxide (FeCo-LDH) and P-doped molybdenum oxide (P-MoO 3) grown in-situ on MXene-modified nickel foam substrate (denoted as P-MoO 3 FCL MXene/NF), with high conductivity, highly hydrophilic properties, and favorable kinetics. Density functional theory calculations (DFT) demonstrate that the electronic engineering tuning of electron dissipation and aggregation at the heterogeneous interface of P-MoO 3 and FeCo-LDH optimizes the electron transfer rate of the active site and the d-band center near the Fermi level, thereby reducing the adsorption energy of H and O reaction intermediates (H*, OH*, OOH*) and improves the intrinsic catalytic activity. As expected, benefiting from the strong chemical and electron synergistic effect between heterogeneous structures, the synthesized P-MoO 3 FCL MXene/NF heterogeneous framework exhibits excellent activity for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) with a low overpotential of 179 mV and 118 mV at 10 mA cm−2, respectively, and Faraday efficiency of up to 96 %. Significantly, the overpotential of 1.53 V is enough to drive a current density of 10 mA cm−2 in a two-electrode configuration which is greatly superior to other bifunctional electrocatalysts. [ABSTRACT FROM AUTHOR]

• Se- and O-co-inserted MoS 2 (Se-MoS 2) is achieved simply by adding Se precursor. • Se-MoS 2 contains abundant 1T phase and S defects. • Se-MoS 2 exhibits outstanding HER activity close to state-of-the-art Pt/C. • DFT calculations indicate that Se-MoS 2 has higher DOS near Fermi energy than MoS 2. • The augment of DOS near Fermi energy conduces to enhance the HER activity of Se-MoS 2. MoS 2 is identified as a potential electrocatalyst for H 2 evolution reaction (HER) due to its low cost and robust durability. However, the limited active site and low electrical conductivity severely hinder the practical application of MoS 2. To address these issues, we herein propose a Se-insertion engineering strategy to fabricate Se- and O-co-inserted MoS 2 (Se-MoS 2) microspheres composed of intertwined nanosheets. Se and O co-insertion create abundant S defects on the basal plane of MoS 2 and thus increase the number of active sites. Additionally, Se and O co-insertion are apt to induce the transition of MoS 2 from 2H to 1T phase (~60% 1T MoS 2), thereby exhibiting more excellent electric conductivity (~2 orders larger than that of MoS 2). Furthermore, optimized Se-MoS 2 not only shows electrocatalytic HER activity (an overpotential of 108 mV at 10 mA cm−2 and a Tafel slope of 47 mV dec–1), also inherits the outstanding electrocatalytic durability of pristine MoS 2. Density function theory (DFT) calculations reveal that the excellent HER performance of optimized Se-MoS 2 can be explained with Volmer-Heyrovsky mechanism, which is intrinsically attributed to the emergence of new band structures near the Fermi energy level of MoS 2 , increasing the electrical conductivity and reducing the Gibbs free energy of hydrogen adsorption. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multilayer hollow MnCo 2 O 4 microsphere with oxygen vacancies was fabricated. • Vo-MnCo 2 O 4 demonstrates an enhanced OER activity and durability. • Oxygen vacancy is critical to the improvement of OER activity. • DFT calculations reveal the effect of oxygen vacancy on the OER activity. Highly efficient and stable electrocatalysts for oxygen evolution reaction are of technological importance in energy conversion and storage. Surface modification is one of the most promising strategies for improving the activity of such electrocatalysts. Herein, we report the multilayer hollow MnCo 2 O 4 microsphere enriched with oxygen vacancies induced by the plasma-engraving technique for the first time. The defective MnCo 2 O 4 microsphere exhibits an excellent catalytic activity and durability as compared to pristine MnCo 2 O 4. Our electrochemical analysis, combined with first-principles calculations, reveals that the improved electrocatalytic performance is attributed mainly to abundant active sites after the plasma treatment and the effects of the introduced oxygen vacancies. The oxygen vacancy not only reduces the density of states near the Fermi level but also lowers the Co d-band center , weakening the adsorption of the intermediates. This facilitates the desorption of the adsorbates, which is necessary for oxygen evolution reaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multilayer hollow MnCo 2 O 4 microsphere with oxygen vacancies was fabricated. • Vo-MnCo 2 O 4 demonstrates an enhanced OER activity and durability. • Oxygen vacancy is critical to the improvement of OER activity. • DFT calculations reveal the effect of oxygen vacancy on the OER activity. Highly efficient and stable electrocatalysts for oxygen evolution reaction are of technological importance in energy conversion and storage. Surface modification is one of the most promising strategies for improving the activity of such electrocatalysts. Herein, we report the multilayer hollow MnCo 2 O 4 microsphere enriched with oxygen vacancies induced by the plasma-engraving technique for the first time. The defective MnCo 2 O 4 microsphere exhibits an excellent catalytic activity and durability as compared to pristine MnCo 2 O 4. Our electrochemical analysis, combined with first-principles calculations, reveals that the improved electrocatalytic performance is attributed mainly to abundant active sites after the plasma treatment and the effects of the introduced oxygen vacancies. The oxygen vacancy not only reduces the density of states near the Fermi level but also lowers the Co d-band center , weakening the adsorption of the intermediates. This facilitates the desorption of the adsorbates, which is necessary for oxygen evolution reaction. [ABSTRACT FROM AUTHOR]

• The Mo atoms were successfully doped into VS 2 matrix for the first time. • The HER performance of VS 2 was significantly enhanced after Mo doping. • Mo-doping can reduce the ΔG H of S site, and strengthen the basal activity of VS 2. • The enhancement of the basal-plane activity is due to charge transfer mechanism. We report the basal-plane catalytic reactivity of VS 2 can be significantly enhanced by Mo doping for hydrogen evolution reaction (HER). Our optimal experiments reveal that the Tafel slope and overpotential at −10 mA cm−2 of VS 2 are reduced by 82.8% and 73.6% respectively after the Mo doping. Furthermore, the turnover frequency at 300 mV and electrochemical surface area of the optimal Mo-doped VS 2 exhibit 19.2- and 27.2-fold enhancements compared with the pure VS 2 , together with significantly improved long-term cycle stability. Our density functional theory (DFT) calculations suggest that Mo dopant reduces the hydrogen adsorption free energy on S sites, and consequently strengthens the basal-plane activity. We uncover a charge transfer mechanism from Mo to the outer surface of S atoms, leading to the enhancement of p-orbital density of states of S at Fermi level and thus far super HER performance. Our findings provide a promising route and theoretical framework to improve the electrocatalytic HER performance of VS 2 , and may have general implications to other transition metal disulfides. [ABSTRACT FROM AUTHOR]

• A supramolecular anchoring strategy is reported to stabilize single-atom-dispersed cobalt. • The Co@g-C 3 N 4 possess a negative Fermi level & a high energy level of d -band position. • Single-site Co atom facilitates the activation of N 2 on the surface of g-C 3 N 4. • Single-site Co atom accelerates the interfacial charge transfer process on g-C 3 N 4. • The Co@g-C 3 N 4 shows improved photocatalytic H 2 evolution and N 2 fixation performances. Ever-increased investigation has been focused on designing photocatalysts comprising intimately interfaced photo-absorbers and co-catalysts for promoting the separation of electron-hole pairs and surface redox reaction. Herein, we present a photocatalytic system in which the single-site-cobalt-atom is firmly trapped and stabilized into the frameworks of porous crimped graphitic carbon nitride (g-C 3 N 4), proposing as advanced photocatalysts for solar-photon-driven hydrogen production and nitrogen fixation. A single molecular source of dicyandiamide was used to partly transformed and then in-situ preorganized into supermolecular precursor, which could coordinate with cobalt ions and manipulate the interactions under elevated temperature prior to the condensation to form atomically Co dispersed g-C 3 N 4 materials. Theoretical evaluation and experimental validation identified that the chemical integration of single-site-cobalt-atom on g-C 3 N 4 is critical in optimizing the electron and band structures and accelerating the interfacial charge transfer process. As a result, the as-obtained Co@g-C 3 N 4 possesses an exceptional photocatalytic hydrogen production rate (2481 μmolh−1g−1, λ > 420 nm) and conspicuous nitrogen photofixation performances under visible-light irradiation. Such concerted catalysis attributes to the negative shift of the Fermi level in Co@g-C 3 N 4 system deriving from the induced charge-transfer effect, which effectively gains the reducibility of electrons and creates more active sites for photocatalytic reactions. [ABSTRACT FROM AUTHOR]

A novel hierarchical Ni/Ni 0.2 Mo 0.8 N heterostructure anchored on N-doped carbon has been developed by a facile NaCl template induced strategy. Both experimental and DFT calculations reveal that the developed catalyst exhibits outstanding electrocatalytic activity and stability towards oxygen evolution reaction (OER) in alkaline media. • Hierarchical Ni/Ni 0.2 Mo 0.8 N@N-C is synthesized by a facile and scalable hard-template route. • Ni/Ni 0.2 Mo 0.8 N nanosheets show unique interfaces nanostructure. • The obtained composite exhibits superior OER performance. • DFT calculations further reveal the synergy effect of the Ni/Ni 0.2 Mo 0.8 N@N-C. Rational development of high-performance and cost-effective electrocatalysts for the oxygen evolution reaction (OER) is of particular importance for renewable energy conversion and storage technologies. Herein, we developed a facile and easily scalable hard-template strategy to fabricate hierarchical Ni/Ni 0.2 Mo 0.8 N nanosheets (~4.37 nm in thickness) in situ coupled with N-doped carbon (Ni/Ni 0.2 Mo 0.8 N@N-C) as an efficient electrocatalyst for the OER. The elaborate construction of Ni/Ni 0.2 Mo 0.8 N can validly regulate the electronic structure, increase the number of active sites, and facilitate diffusion kinetics. Benefiting from the coupling effect between hierarchical Ni/Ni 0.2 Mo 0.8 N and the N-carbon matrix, the resultant Ni/Ni 0.2 Mo 0.8 N@N-C exhibits excellent OER performance in alkaline media, including a low overpotential of 260 mV at 10 mA cm−2, a small Tafel slope of 46 mV dec−1, as well as remarkable stability for long-term electrolysis operation, significantly exceeding the findings for most previously reported OER electrocatalysts. Theoretical studies demonstrate that incorporation of Ni into Ni 0.2 Mo 0.8 N can effectively optimize water adsorption energy and enhance electronic states density near the Fermi level, which is conducive to accelerating the OER process. This work underlines a rational and new perspective for designing inexpensive and robust Mott-Schottky electrocatalysts toward OER for energy storage and conversion devices. [ABSTRACT FROM AUTHOR]