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Optimized electrocatalyst that hybrids with carbon coating FeCoP x nanoparticles possesses catalytic activity toward ORR, OER and HER. Furthermore, through the design of alkali-acid electrolyzer and device integration, for the very first time, a single Zinc-air battery enable to drive an alkali-acid electrolyzer for producing hydrogen and oxygen. [Display omitted] • A one-pot scalable pyrolysis strategy to fabricate a tri-functional electrocatalyst. • High catalytic activity toward ORR&OER in alkaline and HER in acidic media. • The Zn-air battery can run stably for 1500 cycles. • An alkali-acid electrolyzer only requires 0.99 V to release an electrolysis current density of 10 mA cm−2. • A single self-made Zinc-air battery can drive an alkali-acid electrolyzer to produce hydrogen. Developing handy synthesis routes to fabricate low-cost, high-activity, and multifunctional electrocatalysts for a variety of electrochemical reactions is highly desirable so as to achieve the goal that one catalyst can be used for integrated electrolysis devices, thus greatly simplifying the electrocatalyst system processing. Here, we report a one-pot scalable pyrolysis strategy to fabricate a tri-functional electrocatalyst, i.e. , hybrids with carbon coating FeCoP x nanoparticles, which shows favorable electrocatalytic properties toward oxygen reduction reaction, oxygen evolution reaction in alkaline solution, and hydrogen evolution reaction in acidic condition. The new synthesis routes enable us to readily develop an integrated device with a Zn-air battery driving an alkali-acid electrolyzer by just using one catalyst. The present work may shed light on the practical viability of the development of multifunctional electrocatalysts for integrated devices applications. [ABSTRACT FROM AUTHOR]

Transforming carbon dioxide (CO 2) into valuable fuels or chemicals through electrolysis represents a promising approach to reduce the carbon footprint. Conventional CO 2 electrolysis yet faces a challenge in low energy efficiency due to the energy-intensive oxygen evolution reaction (OER) occurring at the anode. In this study, we present an advanced CO 2 electrolysis system that pairs cathodic CO 2 reduction with anodic degradation of hydrazine oxidation reaction (HzOR), enabling efficient CO 2 electrolysis at an ultra-low voltage. To achieve this objective, two precious-metal-free electrocatalysts have been designed and fabricated. Specifically, a nickel single-atom catalyst anchored on porous carbon nanofibers has been developed for cathodic CO 2 -to-CO conversion, while a flower-like Ni 2 Fe 2 N catalyst grown in-situ on nickel foam has been developed for anodic HzOR. We demonstrate high efficiency of CO production (FE CO > 80%) at 100 mA cm−2 with an applied voltage of only 0.45 V by simultaneously degrading hydrazine in a flow cell. [Display omitted] • A promising green electrolyzer coupling CO 2 reduction reaction with hydrazine oxidation reaction (HzOR) was proposed. • The single atomic nickel anchored on porous carbon nanofiber (NiSACs-PCNF) was developed as highly active CO 2 RR catalyst. • The flower-like Ni 2 Fe 2 N in-situ grown on nickel foam (Ni 2 Fe 2 N/NF) was prepared as the effective HzOR catalyst. • The assembled electrolyzer achieved efficient CO production and hydrazine degradation at an ultralow voltage of 0.45 V. • The designed electrolyzer provided a new route for coupling energy-efficient CO 2 upgradation with waste degradation. [ABSTRACT FROM AUTHOR]

• The CoP|S has coral-like nanoporous structures and allows the release of gas evolution in nano-scale design. • Stable nanoporous CoP|S with abundant active sites are fabricated through a simple annealing method. • S-substituting can control the electronic structure and favor more suitable H adsorption of CoP|S to promote HER activity. • Nanoporous CoP|S electrodes present the improved HER performance compared with CoP. The morphology and crystallographic surface can influence the catalytic HER activity of electrocatalyst. With sufficient active sites and surface area, nanoporous materials with three-dimensional interconnected porous networks have shown the promising application in electrocatalyst. In this work, we report a simple method that can synthesize the self-supported nanoporous cobalt phosphosulfate (CoP|S) electrocatalyst. Theoretical calculation shows that the phosphorus substitution by sulfur can control the electronic structures of the active sites and accelerate charge transfer of CoP, therefore improving HER activity. The experimental study shows that nanoporous CoP|S electrodes present the improved HER performance compared with CoP in alkaline media and acidic media, respectively. [ABSTRACT FROM AUTHOR]

Exploring efficient and low-cost oxygen evolution reaction (OER) electrocatalysts is of crucial importance. Here, we report a surface plasmon resonance (SPR) engineering strategy to regulate surface reconstruction of CoFeB nanosheets by decorating plasmonic MoO 2 nanospheres (MoO 2 /CoFeB), in which the SPR effect of MoO 2 offers an additional acceleration for the conversion of inactive Co species to active cobalt oxyhydroxide on the CoFeB surface under visible light. Our results also indicate the real reactive surface for CoFeB is in the form of CoFeOOH with adsorbed BO 2 − that has positive effect. The MoO 2 /CoFeB shows superior OER performance with a low overpotential (209 mV at J =10 mA cm−2). However, such an accelerated reconstruction behavior would be self-terminated once the anodic voltage increases to thoroughly oxidize the MoO 2 to high valence state (+6). This work inspires us to develop a rational strategy to improve the catalytic performance by properly regulating the surface reconstruction. [Display omitted] • SPR effect of MoO 2 was applied for regulating surface reconstruction of CoFeB to enhance the electrocatalytic OER process. • The MoO 2 /CoFeB nanohybrid electrocatalyst shows attractive OER performance with a low overpotential of 209 mV at 10 mA cm–2. • An insightful fundamental understanding of the reaction interface for metal borides was presented. [ABSTRACT FROM AUTHOR]

It is highly desirable to make full use of photogenerated charge carriers by elaborately designing high-efficiency multifunctional photocatalysts with achieving bi-value-added production. Herein, we report the photocatalyst with ultrathin ZnIn 2 S 4 nanosheets decorating polypyrrole nanotubes, thanks to the matched bandgap, is capable of harvesting visible light for photocatalysis, during which the photoexcited electrons and holes are used for H 2 evolution and 1,4-benzenedimethanol (BDM) upgrading oxidation, respectively. Comprehensive experiments and density functional theory calculations indicate that the photoinduced electrons tend to be transferred to the inner PPy nanotubes of PPy@ZIS composite for photocatalytic H 2 generation, while the photoexcited holes favorably oxidize BDM into 1,4-phthalaldehyde (PAD) on outer ZIS nanosheets of PPy@ZIS composite. The optimized PPy@ZIS exhibits an apparent quantum efficiency of 6.43% (at 420 nm) for photocatalytic H 2 evolution and BDM valorization into PAD at a rate of 735 μmol g−1 h−1, remarkably promoting the utilization efficiency of charge carriers. Ultrathin ZnIn 2 S 4 nanosheets are successfully decorated on PPy nanotubes to form hierarchical PPy@ZnIn 2 S 4 composite, which presents highly desirable photocatalytic properties for simultaneous production of H 2 and 1,4-phthalaldehyde via water reduction and 1,4-benzenedimethanol selective oxidation, respectively. [Display omitted] • Hierarchical PPy@ZnIn 2 S 4 nanocomposite was successfully fabricated. • Simultaneous photocatalytic H 2 evolution and 1,4-benzenedimethanol selective oxidation. • PPy nanotubes act as an electrons collector to boost the H 2 production performance. • Selective oxidation of 1,4-benzenedimethanol to 1,4-phthalaldehyde is the carbon-centered free radical process. [ABSTRACT FROM AUTHOR]

[Display omitted] • CdS@ZnIn 2 S 4 hollow cubes are prepared which constitute highly efficient direct Z-scheme photocatalyst. • CdS@ZnIn 2 S 4 can split pure water into H 2 and H 2 O 2 under visible light irradiation. • Visual differentiation between direct Z-scheme and Type II heterojunction is achieved by SPVM. The direct Z-scheme heterojunction has been recently emerging as an appealing architecture for photocatalysts design. Its efficiency depends on the interfacial and structural features of the photocatalysts. Herein, the two-dimensional ZnIn 2 S 4 nanosheets are grown on the surface of CdS hollow cubes to construct the CdS@ZnIn 2 S 4 hierarchical hollow photocatalysts with chemically bonded interface. The visualized measurements based on spatial-resolved surface photovoltage spectroscopy, combined with other spectroscopic and simulation investigations, clearly disclose that the CdS@ZnIn 2 S 4 hollow cubes constitute a highly efficient direct Z-scheme system. This accounts for the stoichiometric generation of H 2 and H 2 O 2 from pure water observed for the CdS@ZnIn 2 S 4 sulfide-only photocatalysts under visible light irradiation with an apparent quantum efficiency of 1.63 % at 400 nm. The present work demonstrates an effective protocol to achieve comprehensive insights into the charge transfer route at semiconductor heterojunction, and offers a viable way for constructing efficient sulfide-only photocatalysts for driving water splitting reaction. [ABSTRACT FROM AUTHOR]

• Ni@NiO-Cu@CuO/NCS is prepared from MOF material via direct calcination process. • Material favors to human urine urea oxidation and groundwater NO 3 − reduction. • Presence of M2+/M3+ redox couple offers better bifunctional catalytic activity. • Substitution of ORR with NRR launches a new branch of fuel cell named UNFC. Though direct urea fuel cells (DUFCs) show promising potential for green energy generation, the practical feasibility of its on-site installation is yet encumbered by the sluggish electrokinetics and low-value product (H 2 O) of oxygen reduction reaction (ORR). We here report the design and synthesis of a bifunctional hybrid electrocatalyst of nitrogen-doped carbon sheets supporting Ni@NiO-Cu@CuO composites (Ni@NiO-Cu@CuO/NCS) via direct calcination of Ni- and Cu-containing metal organic frameworks (MOFs). The as-derived nanohybrid shows impressively high catalytic performance towards urea oxidation reaction (UOR) in alkali and nitrate reduction reaction (NRR) in acidic electrolyte, which inspire us to set up a urea-nitrate fuel cell (UNFC). Owing to the excellent electrochemical characteristics behaviour of prepared nanostructures, the fabricated UNFC simultaneously exhibits improved fuel cell performance of 22.55 ± 2.3 mW cm−2 and degrade the urine and nitrate at the anode and cathode, respectively. The presented innovative electrochemical device may open up a prime step for the development of renewable UNFC for simultaneous green energy generation and N-containing waste removal. [ABSTRACT FROM AUTHOR]

It presents the scalable salt-templated synthesis of two-dimensional porous fluorine-doped carbon (FC) nanosheets with the high active sites and larger special surface area, which shows impressive oxygen reduction reaction (ORR) activities. The synergistic effect of fluoride doping and defects provided more density of active sites in carbon material. It may open up a promising avenue for developing electrocatalysts with high catalytic activity and high stability for electrolyzed application. • Two-dimensional porous fluorine-doped carbon (FC) nanosheets. • Long-term durability and the large active surface area. • Remarkably enhanced oxygen electrocatalytic performance. We present the scalable salt-templated synthesis of two-dimensional porous fluorine-doped carbon (FC) nanosheets. Due to the larger special surface area (1031 m2 g−1) and high active sites, FC-900 (pyrolyzed at 900 °C) shows impressive oxygen reduction reaction (ORR). The synergistic effect of fluoride doping and defects provides richer density of active sites in these nanosheets. When the samples are further calcined at 900 °C for different hours, the ORR activity of the resulting samples shows a little improvement, indicating the influence of the defects on the ORR performance is much inferior to the doped fluorine. The formation of FC structures is beneficial to the ORR activity, and supported by First-principles density functional theory. The results reveal F dopants and defects important role in efficient ORR electrocatalysis owing to the synergistic effect, which is important for comprehending the origin of ORR, and it is also strong evidence to search advanced carbon-based catalysts. [ABSTRACT FROM AUTHOR]

• A sophisticated Ru/3DNCN catalyst were prepared through the template-assisted method. • Ru/3DNCN holds unique 3D porous interconnected structure and plenty of active sites. • Ru/3DNCN exhibits a top-level HER activity and robust stability in a wide pH range. • A Zn-H 2 fuel cell was assembled for hydrogen evolution and electricity generation. The rational design of a highly active, stable and Pt-free electrocatalyst for hydrogen evolution reaction (HER) is critical to the development of renewable energy conversion systems but extremely challenging. Herein, a facile top-down strategy is presented to synthesize ultrafine Ru nanoparticles confined in three-dimensional (3D) porous nitrogen-doped carbon nanosheets (Ru/3DNCN). Compared with the state-of-the-art Pt/C catalyst, the Ru/3DNCN exhibits significantly boosted HER activity and stability over a wide pH range, which only requires the overpotential as low as 37 mV, 66 mV, and 17 mV to achieve a current density of 10 mA cm−2 in 0.5 M H 2 SO 4 , 1.0 M PBS, and 1.0 M KOH, respectively. Moreover, an alkali-acid Zn-H 2 battery is assembled by using the Ru/3DNCN as acid cathode and Zn plate as alkaline anode. Such hybrid battery can fulfill simultaneously hydrogen evolution and electricity generation, thanks to harvesting energy from both neutralization and Zn oxidation. [ABSTRACT FROM AUTHOR]

• A tri-profitable electrochemical cell for energy saving, hydrogen production, gluconate production. • Bifunctional high-activity electrocatalyst of Fe 0.1 -CoSe 2. • Acidic hydrogen evolution and alkaline glucose oxidation. • Electrochemical neutralization energy assisted aqueous electrochemical system. Electrolytic synthesis shows great promise to address the pressing environmental and energy issues by synergy with the ever increasing renewable energy. In this article, we report a tri-profitable alkaline-acidic asymmetric electrolytic cell (3A-EC) by coupling glucose oxidation reaction (GOR) in alkaline anode with hydrogen evolution reaction (HER) in acidic cathode. We design and fabricate bifunctional electrode with iron doped cobalt diselenide nanowires on conductive carbon cloth (Fe 0.1 -CoSe 2 /CC), which shows highly attractive electrocatalytic activity and stability for GOR in alkali and HER in acid, respectively. The as-built 3A-EC only requires an applied voltage of 0.72 V to achieve an electrolytic current density of 10 mA cm−2 for H 2 and gluconate generation, thanks to successfully harvesting electrochemical energy from both glucose oxidation and neutralization. The present work presents an innovative strategy of killing three birds with one stone for saving energy and generating two value-added products. [ABSTRACT FROM AUTHOR]

One type of Pt-like electrocatalysts consisting of N,P-codoped porous carbon-encapsulated ultrafine RuP 2 nanoparticles has been developed for pH-universal hydrogen evolution reaction. • A facile and general synthetic method was developed for the fabrication of robust ruthenium diphosphide nanoparticles. • Imidazolium-based ionic polymer inhibits the aggregation of ruthenium diphosphide during phosphorization. • The bifunctional catalyst showsplatinum-like activity in pH-universal hydrogen evolution reaction. Development of cost-effective and durable electrocatalysts with Pt-like activity for pH-universal hydrogen evolution reaction (HER) is highly desirable but challenging. Herein, we report a new methodology for facile fabrication of robust electrocatalysts consisting of N, P-codoped carbon (NPC)-encapsulated RuP 2 nanoparticles around carbon nanotubes (CNTs), which shows unprecedented HER activity and high durability in all-pH range. The method involves the conformal coating of the imidazolium-based ionic polymer (ImIP) on CNTs surface, anion metathesis and subsequent phosphorization, the multistep synthetic protocol allows for deliberate modulation of the electrocatalysts. ImIP effectively inhibits the aggregation of RuP 2 during phosphorization to form small-sized RuP 2 nanoparticles, while NPC significantly increases the conductivity, intrinsic activity and stability of RuP 2. The remarkably low overpotentials of 12, 15 and 13 mV are required to achieve a current density of 10 mA cm−2 in 1.0 M KOH, 1.0 M PBS and 0.5 M H 2 SO 4 , respectively. This work provides a feasible method to develop new type of Pt-like electrocatalysts for HER in all-pH range. [ABSTRACT FROM AUTHOR]

• A family of porous metal-porphyrin triazine-based frameworks (MPTFs) were developed. • NiPTFs-600 exhibited a superb activity of electrocatalytic reduction of CO 2 (ECR-CO 2). • The superb ECR-CO 2 was attributed to abundant N species and Ni-N x active sites. Electrochemical reduction of CO 2 (ECR-CO 2) into high value-added products plays a crucial role in energy conversions. Herein, we developed a family of porous metal-porphyrin triazine-based frameworks (MPTFs-x, M = Mn, Fe, Co, Ni, and Cu, x = temperature) with a specific surface area up to 977 m2 g−1 and homogenously dispersed transition-metals. Benefiting from a high content of N species of 8.43 at.% and abundantly exposed Ni-N x active sites, NiPTFs-600 displayed a superb Faradaic efficiency (FE) of CO production (>90 %) in the range of −0.55 V to −0.95 V with the maximum FE of 97.6 % and current density of 10.8 mA cm-2 at −0.8 V. The reaction mechanism was found to be the adsorption of CO 2 molecules to form *CO 2 intermediates, accompanied by successive protonation to produce *COOH and then *CO. [ABSTRACT FROM AUTHOR]

A novel exfoliated NbS 2 nanosheets produced via liquid exfoliation method exhibited an excellent catalytic activity for nitrogen reduction reaction. • A novel exfoliated NbS 2 nanosheets was produced via liquid exfoliation method. • Exfoliated NbS 2 nanosheets exhibited an excellent catalytic activity for NRR. • The Nb4+ species of exfoliated NbS 2 nanosheets was acted as active sites. • Exfoliated NbS 2 nanosheets was acted as the cathode for a Zn-N 2 battery. • Solar-driven NRR-OER device was achieved with exfoliated NbS 2 nanosheets. Electrochemical nitrogen reduction reaction (NRR) under mild conditions is an attractive prospect for ammonia synthesis. However, this process faces with poor ammonia yield rate and low Faradic efficiency. Herein, we developed exfoliated metallic niobium disulfate (NbS 2) nanosheets for an electrochemical NRR. Owing to more exposed active sites and high electron transfer ability, the exfoliated NbS 2 nanosheets show an extraordinary activity for electrochemical NRR. A high Faradaic efficiency of 10.12 % with an ammonia yield rate of 37.58 μg h−1 mg−1 cat is achieved at −0.5 V versus reversible hydrogen electrode (RHE). The Nb4+ species of exfoliated NbS 2 are confirmed as active sites for NRR. When the exfoliated NbS 2 nanosheets are further assembled into a Zn-N 2 battery and serve as the cathode, an energy density of 714 mA h g−1 with a power density of 0.31 mW cm−2 is achieved. Notably, electrochemical NRR on exfoliated NbS 2 nanosheets can be further driven by solar energy. [ABSTRACT FROM AUTHOR]

• The UiO-66@ZnIn 2 S 4 nanocomposites with UiO-66 nanoparticles being encapsulated by ZnIn 2 S 4 nanosheets were fabricated. • The intimate contact interface was found between UiO-66 and ZnIn 2 S 4. • The heterostructure significantly enhanced visible-light-driven H 2 evolution. • UiO-66 was acted as a trap site of photogenerated electrons in the heterostructure. It is highly desirable to develop efficient visible-light-driven photocatalysts for hydrogen production from water splitting. We herein report a rational design for reliable and convenient fabrication of a set of nanocomposites with ZnIn 2 S 4 nanosheets encapsulated UiO-66 octahedral nanoparticles (UiO-66@ZnIn 2 S 4). The comprehensive characterizations verify ZnIn 2 S 4 nanosheets are uniformly decorating on UiO-66 octahedral nanoparticles. The systematic studies demonstrate the UiO-66@ZnIn 2 S 4 (U@Z) holds favorable features to facilitate effective separation and transfer of photochemical charges, thanks to intimate contact interfaces and a well-matched band structure between UiO-66 and ZnIn 2 S 4. The optimal nanocomposite exhibits high photocatalytic activity for hydrogen production under visible light illumination, generating hydrogen at an impressive rate of up to 3061.61 μmol h−1 g−1, with an apparent quantum efficiency of 9.84% under the incident monochromatic light of 420 nm. [ABSTRACT FROM AUTHOR]