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The directional synthesis of transition metal phosphides was considered to be an effective strategy to solve the overdependence of noble metals on photocatalytic hydrogen evolution (PHE) reactions. Inspiringly, this work reported a facile method for constructing hollow Co 2 P nanocages (Co 2 P NCGs) that derived from ZIF-67 by calcining and phosphiding procedure in nitrogen atmosphere to act as non-noble metal cocatalysts. Followed with further coating thin-layered ZnIn 2 S 4 (ZIS) on the surface of Co 2 P NCGs through a hydrothermal reaction, the hierarchical robust Co 2 P/ZnIn 2 S 4 nanocages (Co 2 P/ZIS NCGs) were then delicately fabricated as efficient photocatalysts for PHE reactions. The uniquely hollow structure of Co 2 P NCGs largely diffused the photogenerated chargers that induced from ZIS and the closely interfacial contact significantly promoted the separation and transfer of electrons from ZIS to Co 2 P according to density functional theory (DFT) calculation, synergistically resulting in an efficient hydrogen generation performance. PHE results showed that an efficient H 2 evolution rate of 7.93 mmol/g/h over 10% Co 2 P/ZIS NCGs was achieved, about 10 times higher than that of pristine ZnIn 2 S 4. More importantly, the hierarchically hollow Co 2 P/ZIS NCGs exhibited ascendant PHE activity in comparison with that of 1% noble metal (Pt, Au, Ag) loaded ZnIn 2 S 4 with superior sustainability, all indicating the efficient and stable photocatalysts of Co 2 P/ZIS NCGs for PHE reactions. [ABSTRACT FROM AUTHOR]

In this work, we report a facile method to prepare P, N co‐doped porous carbon (PNPC) by the carbonization of covalent organic polymer (COP) used as efficient metal‐free electrocatalyst for hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). Overpotential is only 150 mV for the PNPC electrocatalyst to reach 10 mA cm−2 in the acidic medium due to the heteroatom dopants in the carbon matrix; meanwhile, stable HER activity is recorded during 5000 potential cycles. Additionally, overpotential is 343 mV for PNPC electrocatalyst to drive OER catalysis with 10 mA cm−2, which is comparable to the benchmarked IrO2 (320 mV). Similarly, PNPC electrocatalyst can achieve a Pt‐like ORR catalytic activity. The power density of the assembled rechargeable zinc‐air battery (ZAB) is 1.8 times higher than that of the commercial system (Pt/C−IrO2) and charge‐discharge voltage gap is well maintained during 20 h test, implying the high stability of the formed PNPC electrocatalyst. [ABSTRACT FROM AUTHOR]

W/W2C heterostructured nanoparticles encapsulated by N,P dual-doped carbon (W/W2C@NPC) fabricated by the carbonization of in situ polymerized polyaniline (PANI) and phosphotungstic acid require low overpotentials of 55 mV and 82 mV vs. RHE to achieve a cathodic current density of 10 mA cm−2 in acidic and alkaline electrolytes, respectively. [ABSTRACT FROM AUTHOR]

As well known, heteroatom doped carbon material served as metal‐free electrocatalyst for hydrogen evolution (HER) and oxygen reduction reactions (ORR) particularly relies on the heteroatom doping level. Here, we report a 3D porous nitrogen doped carbon (PNC) electrocatalyst with superior HER and ORR electrocatalytic activities derived from the calcination of the discarded cigarette butt and dicyandiamide possessing a high nitrogen content (20 at%). PNC electrocatalyst only demands 143 mV versus RHE to achieve 10 mA cm−2 ascribed to the high nitrogen percentile in PNC electrocatalyst favorable for constructing successive active centers contributing to efficiently catalyzing HER. Ignorable degradation in HER activity observed after 10000 potential cycles as well as undetectable decay in HER performance recorded after 12 h operation indicate high stability of PNC electrocatalyst. Meanwhile, half‐wave potential of PNC electrocatalyst reaches 0.81 V versus RHE in 1 M KOH electrolyte. Additionally, stable ORR activity attained after 1000 potential cycles is indicative of high stability. A comparably high zinc‐air battery performance with maximum power density of 66 mW cm−2 is achieved by PNC electrocatalyst. This study highlights the importance of nitrogen doping level in metal‐free electrocatalyst for boosting HER and ORR activities. What? No metal! A 3D porous nitrogen doped carbon (PNC) electrocatalyst with superior HER and ORR electrocatalytic activities derived from the calcination of the discarded cigarette butt and dicyandiamide possessing a high nitrogen content (20 at%). [ABSTRACT FROM AUTHOR]

[Display omitted] • Hollow tubular ZnIn 2 S 4 modified with embedded metal-organic-framework-layers (ZnIn 2 S 4 -MOFL) were rationally designed. • Efficient ZnIn 2 S 4 -MOFL released H 2 bubble at the optimum rate of 28.2 mmol/g/h. • The Z-scheme photocatalytic system strongly promoted the separation of electron and hole pairs. • DFT results revealed the decreased density of states of ZnIn 2 S 4 after coupling with the organic ligands of MOFL. This work reported a facile one-step method for constructing hollow tubular ZnIn 2 S 4 modified by metal-organic-framework-layers (MOFL) with In-MOF as precursor to be efficient photocatalysts (ZnIn 2 S 4 -MOFL) for robust photocatalytic hydrogen evolution (PHE). The dominant catalyst of ZnIn 2 S 4 and cocatalytic role of MOFL synergistically promoted the separation of electron and hole pairs due to the direct Z-scheme photocatalytic system, leading to an extraordinarily high PHE activity. The density functional theory (DFT) results revealed the remarkably decreased density of states (DOS) of ZnIn 2 S 4 after coupling with the organic ligands of MOFL, indeed proving an effectively suppressed recombination of charge carriers and benefited the performance of photocatalytic reactions. Experimental PHE results showed that a large number of hydrogen bubbles were visible to naked eyes and the optimal hydrogen evolution reached 28.2 mmol/g/h, the highest value reported so far among ZnIn 2 S 4 -based photocatalysts, and almost 14.8 times higher than that of pristine ZnIn 2 S 4. More importantly, the superior apparent quantum efficiencies (AQEs) of 22.67 % at monochromatic light (350 nm) and the stable hydrogen generation capability (5.7 mmol/g/h) under real sunlight irradiation all confirmed a promising catalyst of ZnIn 2 S 4 -MOFL for hydrogen evolution applications. [ABSTRACT FROM AUTHOR]

• Nitrogen atoms in Ni@NCNT facilitate the in-situ conversion of metallic Ni to Ni3+ species. • Nitrogen atoms in Ni@NCNT weaken the interaction between Ni3+ and CO 2 in urea oxidation. • 1.56 V is required to achieve 10 mA cm−2 in overall urea oxidation for Ni@NCNT. Urea electro-oxidation is an attractive and alternative anodic reaction in the electrochemical generation of hydrogen using wastewater ascribing to the low theoretical voltage and non-precious metal (nickel) catalyst for urea oxidation reaction (UOR); however, the sluggish UOR and poisoning of catalyst impede the practical application. Here, in this work, we synthesize a series of nickel nanoparticles embedded nitrogen doped carbon nanotubes (Ni@NCNT) and study the effect of nitrogen dopants on UOR catalytic activity. The nitrogen dopants can weaken the binding strength between CO 2 species and active sites resulting in alleviation of CO 2 poisoning; simultaneously, nitrogen dopants also promote the in-situ conversion of Ni3+ species facilitating UOR catalysis; as a result, electrocatalytic current density of 45.8 mA cm−2 is recorded for Ni@NCNT in 1 M KOH electrolyte with 0.5 M urea at 1.5 V vs. RHE, which is 3.8 fold better than commercial Pt/C (11.8 mA cm−2). Moreover, Ni@NCNT, due to the more nitrogen dopants, exhibits a comparable overpotential to commercial Pt/C for driving hydrogen evolution reaction (HER) catalysis in 1 M KOH electrolyte at high current density (400 mA cm−2). Subsequently, 1.56 V is demanded for overall UOR catalysis on Ni@NCNT with current density of 10 mA cm−2. This work offers useful information for designing a stable and efficient electrocatalyst for not only UOR but also electrochemical generation of H 2 from wastewater. [ABSTRACT FROM AUTHOR]

• Flower-like ZnIn 2 S 4 coupled with black phosphorus (BP) as efficient photocatalyst. • BP and photo-deposited Pt played a synergistic role in enhancing photocatalytic H 2 evolution. • 0.5%Pt/0.5%BP/ZnIn 2 S 4 showed the best H 2 production efficiency at 1278 μmol/g/h. • Superior recycling stability of more than 4 cycles for solar hydrogen evolution. To make persistent efforts at enhancing hydrogen evolution driven by solar energy, this work, for the first time, had introduced flower-like ZnIn 2 S 4 coupled with black phosphorus (BP) as efficient photocatalyst for hydrogen evolution with photo-deposited Pt assisted under visible light irradiation. The hydrogen evolution efficiency of BP, ZnIn 2 S 4 , 0.5%BP/ZnIn 2 S 4 , 0.5%Pt/BP, 0.5%Pt/ZnIn 2 S 4 and 0.5%Pt/0.5%BP/ZnIn 2 S 4 photocatalysts were successively conducted and results showed that both BP and Pt played an important role in enhancing the photocatalytic hydrogen evolution rate. Therefore, the ternary 0.5%Pt/0.5%BP/ZnIn 2 S 4 composite exhibited the strongest hydrogen production efficiency at 1278 μmol/g/h, about 10 times higher than that of pristine ZnIn 2 S 4 (131 μmol/g/h) and represented a highly stable characteristic after suffering four recycles. The promoting hydrogen evolution of ternary photocatalyst could be ascribed to the unique bandgap and larger two-dimensional plane structure of BP, which provided abundant landing sites for the anchor of flower-like ZnIn 2 S 4 , thus leading to a well-inhibited recombination and efficient separation of photogenerated electrons and hole pairs between ZnIn 2 S 4 and BP. The remarkable photocatalytic hydrogen evolution performance and prominent stability all indicated that 0.5%Pt/0.5%BP/ZnIn 2 S 4 was a promising photocatalyst candidate for solar hydrogen production. [ABSTRACT FROM AUTHOR]

The photocatalytic evolution of hydrogen (H2) from water splitting is considered a promising route to overcome the energy crisis, and the key lies in the preparation of efficient photocatalysts. Herein, superior ordered sponge-like carbon self-doped graphitic carbon nitride (g-C3N4) nanosheets (SCCNS) were prepared via a combined strategy of melamine–cyanuric acid complex supramolecular pre-assembly and solvothermal pre-treatment using ethylene glycol (EG) aqueous solutions (EG:water = 50:50 vol.%) as a solvent and carbon doping source. The following pyrolysis converts the naturally arranged melamine–EG–cyanuric acid supramolecular intermediates to highly crystalline SCCNS with large specific surface areas. The optimal SCCNS-180 exhibits superior photocatalytic H2 evolution activities (∼4393 and 11 320 μmol h−1 g−1) when irradiated with visible light and simulated sunlight; these values are up to ∼17- and ∼18-fold higher than that of bulk g-C3N4. The quantum efficiency of SCCNS-180 at λ = 420 nm can reach 6.0%. The excellent photocatalytic performance of SCCNS-180 derives from its distinct ordered sponge-like nanosheet structure with highly crystallinity and the carbon doping, leading to its improved optical absorption, accelerated photoinduced electron–hole pair transfer and separation rate and enlarged specific surface area (134.4 m2 g−1). [ABSTRACT FROM AUTHOR]

Constructing high-performance catalyst for hydrogen evolution reaction (HER) is the effective way to eliminate energy crisis. Reasonable engineering of heterointerfaces can effectively create more active sites and promote electron transfer resulting in improvement in the catalytic activity. In this work, we synthesize the well-defined molybdenum carbides and tungsten carbides nano-heterostructure (Mo 2 C/W 2 C) by carbonization with CH 4 /H 2 at 800 °C showing excellent HER activity, fast kinetics and electrochemical stability in both alkaline and acidic electrolytes. Mo 2 C/W 2 C requires only 140 and 132 mV overpotentials to reach catalytic current density of 10 mA cm−2 in 0.5 M H 2 SO 4 and 1 M KOH electrolyte, respectively. Tafel slope is as low as 51 and 76 mV dec−1 in 0.5 M H 2 SO 4 and 1 M KOH comparable to the benchmarked Pt/C. Moreover, Mo 2 C/W 2 C exhibits a superior stability with slight deterioration in HER performance after 5000 potential cycles. This work elucidates that the rational construction of heterointerfaces is favorable for design of efficient non-noble metal electrocatalyst for HER catalysis. Image 1 • Mo 2 C/W 2 C heterogeneous electrocatalyst is successfully synthesized. • The overpotential is 140 mV for Mo 2 C/W 2 C to deliver 10 mA cm−2 in acidic medium. • Mo 2 C/W 2 C requires 132 mV overpotential to reach 10 mA cm−2 in alkaline medium. [ABSTRACT FROM AUTHOR]

• Atomic layer Co 3 O 4-x nanosheets (1 nm) are synthesized. • Robust OER and ORR activities are achieved for atomic layer Co 3 O 4-x nanosheets. • Rechargeable ZAB performance of Co 3 O 4-x nanosheets is 1.7 fold than Pt/C-IrO 2. Stable and efficient bifunctional electrocatalyst for air electrode is still of challenge for rechargeable zinc-air batteries (ZABs). Here, we report an atomic layer oxygen defect cobalt oxides (Co 3 O 4-x) nanosheets (1 nm) as efficient electrocatalyst for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Due to the atomic layer nanosheets, more oxygen defects are formed during plasma treatment enabling effective OER catalysis with overpotential of only 309 mV, which is lower compared to benchmarking IrO 2 (313 mV). Meanwhile, a Pt-like ORR activity is achieved for Co 3 O 4-x due to the atomic layer nanosheets with highly exposed active sites and loosened binding strength between Co3+ and O 2 /OH−. The battery performance of Co 3 O 4-x nanosheets is 1.7 times higher than that of Pt/C-IrO 2 based ZABs. Besides, Co 3 O 4-x nanosheets exhibit undetectable degradation in battery performance after galvanostatic discharge-charge with 5 mA cm−2 for 150 h implying the superior stability of the atomic layer Co 3 O 4-x nanosheets. All-solid-sate ZABs fabricated from Co 3 O 4-x nanosheets perform an impressive power density of 57 mW cm−2 and stable galvanostatic discharge-charge voltage for 2 h demonstrating that Co 3 O 4-x nanosheets can be utilized as air electrode for practical application. [ABSTRACT FROM AUTHOR]

Defect-rich tungsten disulfide (WS2) nanosheets are synthesized via a self-template method, in which tungsten oxide is partially sulfurized to form WS2/WO3 nanosheets. The defect-rich WS2 nanosheets only require an overpotential of 145 mV to achieve a current density of 10 mA cm−2 with a Tafel slope of 58.5 mV dec−1 and exhibit excellent stability in 0.5 M H2SO4 electrolyte. [ABSTRACT FROM AUTHOR]

Cu-Ru dual atoms anchored to N-doped phosphorene shows the synergy effect to achieve nitrogen reduction efficiently [Display omitted] • Cu-Ru dual atoms show the synergy effect and promote the eNRR property of Cu based catalyst. • Cu-Ru/N 4 -BP shows excellent eNRR property than HER property. • The lower NH 3 desorption energy makes catalytic sites be exposed again, benefiting for higher catalytic activity. • N 2 molecules can be reduced into NH 3 on the Cu-Ru/N 4 -BP with the ultra-lower overpotential of 0.30 V. The Harber-Bosch method was considered as a milestone in the field of industrial production because this method can utilize N 2 to produce NH 3. However, this process severely consumes energy resources and produces a mass of undesirable byproducts and pollution, which unsatisfied the international consensus of "carbon neutrality". Exploring an efficient electrocatalyst for achieving N 2 reduction is becoming extreme imperative for the novel catalytic design. Here, we constructed 17 kinds of Cu based transition metal dual atoms anchored to N-doped phosphorene electrocatalyst (Cu-TM/N 4 -BP) as the potential candidates for the N 2 fixation based on the first-principles calculations. The Ru atom promotes the N 2 adsorption property of Cu atom, stretches N≡N triple bond, and thus activates N 2 molecules. The Cu-Ru dual atoms anchored to N-doped phosphorene (Cu-Ru/N 4 -BP) shows excellent N 2 reduction property than hydrogen evolution reaction. The N 2 molecules can be efficiently reduced into NH 3 on the Cu-Ru/N 4 -BP with the ultra-lower overpotential of 0.30 V and NH 3 desorption energy. This study provides a novel way at the atomic level to explore phosphorene based electrocatalyst with lower overpotential and long durability for N 2 reduction in the experiments. [ABSTRACT FROM AUTHOR]

Here, we report a facile method to synthesize ruthenium phosphides with diameter 1 nm and an amorphous structure at room temperature. Only 31 mV vs. RHE overpotential is required to deliver 10 mA cm−2 and no degradation in hydrogen evolution reaction (HER) performance is recorded after 24 h of catalysis at 100 mA cm−2. [ABSTRACT FROM AUTHOR]

Highly active and stable electrocatalysts at low cost for hydrogen evolution reaction are essential for large scale hydrogen production. The Ni 3 P-Ni heterostructure confined in 3D networks of carbon nanotube (CNT) has been successfully prepared as the hydrogen evolution reaction (HER) electrode. The morphology and phase composition of Ni 3 P-Ni heterostructure are tunable by varying the acid pickling time. The Ni 3 P-Ni/CNT composite electrode with optimized Ni:Ni 3 P ratio of 22.29 wt% demonstrate high catalytic activity and excellent stability for HER. It demonstrates a comparable HER activity to the standard Pt electrode in alkaline solution, i.e., overpotentials of 116 vs 67 mV at 10 mA·cm−2 and Tafel slops of 59 vs 37 mV·dec−1. No degradation is observed after 1000 cyclic voltammetry (CV) cycles or 50 h operation under constant 0.3 V overpotential. • Pickling affects the morphology of heterogeneous structure and the content of Ni. • The Ni 3 P-Ni heterostructure was anchored to the carbon nanotube network by ball milling. • The electrode was prepared by mixing with PTFE and pressing. • The results show that Ni 3 P-Ni/CNT electrode has the best hydrogen evolution activity when the Ni/Ni 3 P ratio is 22.29 %. [ABSTRACT FROM AUTHOR]

[Display omitted] • NiS/rGO/Cd 0.3 Zn 0.7 S photocatalysts prepared by facile hydrothermal and photochemical methods. • NiS are uniformly distributed on C 0.3 Z 0.7 S nanorods. • The NiS/rGO/C 0.3 Z 0.7 S exhibits excellent photocatalytic H 2 evolution activity of 1058 μmol h−1. • A possible mechanism was proposed based on the synergistic effect of rGO and NiS. Effectively improving the separation efficiency of photoinduced carriers is of crucial importance for the design of photocatalysts with excellent hydrogen evolution activity. Herein, by combining CdZnS nanorods with rGO and further depositing NiS as cocatalysts, the separation and transfer of photoinduced carriers for CdZnS is significantly improved. Without using any noble metals as cocatalysts, the optimal NiS/0.5%rGO/C 0.3 Z 0.7 S exhibits an outstanding H 2 evolution activity of 1058 μmol h−1 under visible light illumination, which is evidently better than that of pure CdZnS nanorods and most CdZnS-based photocatalysts reported previously. Our study indicates that the introduction of rGO can effectively assist the transfer of photoinduced electrons and evenly distributed NiS on the surface, as the active center for H 2 evolution reaction, can easily capture photoinduced electrons to participate in photocatalytic process. Thus, the synergistic effect of rGO and NiS is considered to be the main cause for the improved photocatalytic performance. This work could offer a facile and low-cost strategy for the construction of composite photocatalysts with high-efficiency hydrogen generation activity. [ABSTRACT FROM AUTHOR]

• CoWO 4-x @C exhibits comparable HER activity to Pt/C in acidic and alkaline mediums. • CoWO 4-x @C requires only 295 mV overpotential to deliver 10 mA cm−2 in the OER test. • 1.57 V is required for CoWO 4-x @C to attain 10 mA cm−2 in alkaline water splitting. Development of earth-abundant, efficient and stable electrocatalysts for water splitting is of crucial importance for environmentally friendly energy conversion and storage. Here, we report an oxygen deficient cobalt tungstate nanoparticles with diameter of 8 nm (CoWO 4-x @C) as efficient bifunctional electrocatalyst for hydrogen evolution reaction (HER) and oxygen reduction reaction (OER), which exhibits comparable HER activity to commercial Pt/C with overpotentials of 32.5 mV and 46.8 mV vs. RHE to deliver current density of 10 mA cm−2 in acidic and alkaline mediums, respectively, ascribed to the rich oxygen vacancies facilitating the hydrogen adsorption and its relative recombination, respectively. Additionally, undetectable degradation is observed for CoWO 4-x @C after 10,000 potential cycles indicating high durability. Meanwhile, CoWO 4-x @C requires only 295 mV overpotential to deliver 10 mA cm−2 in the OER test, which is better than the benchmarking IrO 2 (313 mV). 1.57 V comparably lower than Pt/C-IrO 2 (1.59 V) is required for achieving the water splitting current density of 10 mA cm−2 without any degradation for 12 h. [ABSTRACT FROM AUTHOR]