Highly active and durable bifunctional catalysts play a crucial role in enabling the efficient water electrolysis. In this study, a three-dimensional hierarchical structure was constructed by epitaxially growing NiFeCoCuMo high-entropy alloys (HEAs) nanowires​ on a spherical Ni3S2‑modified Ni foam substrate (HEAs@Ni3S2@Ni foam). The introduced Ni3S2 interlayer serves as an orientation-regulating template, promoting the epitaxial growth of HEAs and optimizing interfacial charge transfer dynamics. The resulting HEAs-based composite electrode demonstrates ultralow overpotentials of 186 mV for HER and 275 mV for OER at 500 mA·cm-2. As a bifunctional catalyst in an AEM water electrolyzer, it achieves a low cell voltage of 1.80 V at 1.0 A·cm-2, demonstrating excellent stability over 225 hours at 0.6 A·cm-2 and 100 hours at 1.0 A·cm-2. This work establishes a novel design paradigm for high-performance bifunctional catalysts in AEM water electrolysis, offering a promising pathway toward scalable green hydrogen production.

Alkaline water electrolysis is considered an optimal technology for large-scale production of green hydrogen because of its economic and mature characteristics. The separator plays a crucial role in the alkaline water electrolysis process, as it fulfills the functions of gas separation and electrolyte transport. Nevertheless, the development of advanced separators with low ohmic resistance, high gas barrier ability, and good durability simultaneously remains a major challenge. Here, we first fabricated a series of high-performance composite separators with a porous bicontinuous structure by employing a nonsolvent-induced phase separation technique using a "weak solvent" (a solvent with a low affinity toward the membrane-forming polymer). The unique porous bicontinuous structure endows the membranes with high porosity, narrow pore size distribution with nanopores, and good hydrophilicity. As a result, the composite separator exhibits not only a low area resistance (0.13 Ω·cm2) but also a high bubble point pressure (5.1 bar). The composite separator also displays excellent durability in both long-term electrolysis and alkaline-aging tests.

Direct seawater electrolysis offers a promising route for sustainable hydrogen production, particularly in offshore applications, yet challenges such as high overpotentials at industrial current densities and chloride-induced corrosion hinder its scalability. Herein, we report a phosphorus-doped NiFe electrode (P-NiFe-NF) synthesized via a scalable electrodeposition and vapor-phase deposition approach. The optimized P-NiFe-NF electrode achieves a low oxygen evolution reaction (OER) overpotential of 282 mV at 400 mA/cm² in simulated seawater and demonstrates exceptional stability for 175 hours under continuous operation at 400 mA/cm². The incorporation of phosphorus facilitates the in situ formation of a phosphate-rich surface layer, effectively repelling chloride ions and suppressing competitive chlorine evolution. Combined with the synergistic catalytic activity of Ni and Fe, this design enables high efficiency and durability at industrial-relevant current densities. The simplicity of the fabrication process and robust performance highlight its potential for large-scale hydrogen production from seawater.

Effective charge separation and transfer at the semiconductor-cocatalyst interface are essential for efficient photoelectrochemical (PEC) water splitting. However, identifying an appropriate interlayer to promote interfacial charge transfer remains a substantial challenge. Herein, a hole transport layer (HTL) composed of NiFe layered double hydroxide (NiFe-LDH) was introduced onto a nanoporous BiVO4 photoanode to suppress interfacial charge recombination. Spectroscopic analyses reveal that the incorporation of the NiFe-LDH HTL facilitates the formation of a favorable energy band alignment, enabling efficient extraction of photogenerated holes from BiVO4 and significantly reducing both interfacial and bulk recombination losses. The subsequent deposition of Co3Ge2O5(OH)(4) as the oxygen evolution catalyst (OEC) further enhances the charge transfer kinetics and surface oxygen evolution reaction (OER) activity, as verified by photoelectrochemical experiments and theoretical calculations. Consequently, the BiVO4/NiFe-LDH/Co3Ge2O5(OH)(4) photoanode achieves a photocurrent density of 5.15 mA/cm(2) at 1.23 V versus the reversible hydrogen electrode (V-RHE), along with excellent operational stability. Additionally, charge separation and injection efficiencies of 92.6% and 87.2% are achieved at 1.23 V-RHE, respectively. These findings underscore the critical role of the HTL in tailoring interfacial energetics to advance efficient solar water oxidation.

Developing high-performance oxygen evolution catalysts remains crucial for advancing the efficiency and costeffectiveness of anion exchange membrane (AEM) water electrolysis. Herein, we reported a scalable synthesis strategy for Mo-modified NiFe layered double hydroxide (LDH) nanoflowers (NFM-OED) through top-down oxidation etching of amorphous NiFeMo oxide precursors in alkaline. The selective leaching of Mo species from the amorphous precursor induces phase transformation into an LDH structure with intercalated MoO42- . The MoO42- species mediate the structural evolution to catalytically active NiOOH during the oxygen evolution reaction (OER). Notably, preserving the etching products in a slurry form improves the dispersion of LDH nanoparticles, thereby facilitating the formation of a catalyst layer with exceptional conductivity. The NFM-OED electrocatalyst exhibits outstanding OER activity, delivering a low overpotential of 260 mV at 10 mA cm- 2 in the absence of conductive carbon additives. Besides, a membrane electrode assembly fabricated with the NFM-OED anode achieves an AEM electrolyzer cell voltage of 1.73 V at 1.0 A cm- 2 in 1 M KOH at 60 degrees C, with remarkable stability for 600 h at 1.0 A cm- 2 and 100 h at 2 A cm- 2. These findings provide fundamental insights into the intercalation modification of LDH catalysts and emphasized the crucial role of catalyst preservation form in optimizing OER performance for practical AEM water electrolysis applications.

In the field of photocatalytic water splitting, the strategy of doping photocatalysts has emerged as a significant and extensively studied approach. Doping can effectively facilitate the modification of both the microstructure and energy band structure of the photocatalyst, addressing key performance limitations such as light absorption, position of the conduction and valence band minima (CBM and VBM), photogenerated carrier separation, and surface chemical reactions. In recent years, we have reported several works about the doping of rare earth elements into bismuth-based composite oxides. These endeavors are aimed at enhancing the conduction band minimum and achieving overall water splitting under visible light. Based on these bismuth-based composite oxides, we studied the effects of doping on the microstructures of photocatalysts, including exposed surfaces, surface properties, and defects. Recently, we introduce an innovative asymmetric doping technique—Selected Local Gradient Doping, intricately placing doped ions within nanocapsules. This approach allows for the gradual, controlled, and localized release of doped ions to the primary photocatalyst. Therefore, this account is to review our related research in the field of doping for photocatalytic water splitting. The primary focus on doping bismuth-based composite oxides and Asymmetry doping would significantly make contribution to the exploration of novel materials for photocatalytic water splitting under visible light and the enhancement of energy conversion efficiency.

The light penetration effect will weaken the driving force of charge separation from phase to surface by the built-in electric field of nanoscale photocatalysts, like low-dimensional materials. Therefore, in this study, a novel nanoscale lamination catalyst design method was proposed using a polymeric carbon nitride (PCN)-nano polyhedral SrTiO3 core-shell structure catalyst (PCN-SrTiO3). The results showed that the nanoscale lamination effect could be generated by the formation of the N–Sr bond, which could regulate the built-in electric field of the PCN simultaneously. Moreover, detailed char-acterization indicated that the N–Sr bond, which facilitates the generation of N vacancies in PCN, could act as a novel channel for charge transfer. Both surface and interior core N-deficient PCN have been discovered, resulting in more positive and negative VB positions, respectively. Synchronously, the light absorption ability of the PCN-SrTiO3 samples increased. Consequently, the enhanced pho-tocatalytic overall water splitting could be ascribed to the synergism of the built-in electric field regulation caused by the N-Sr formation-induced nanoscale lamination effect, which was favorable for energy flow adaption on the spatiotemporal scale.

Step-scheme (S-scheme) heterojunctions in photocatalysts can provide novel and practical insight on promoting photogenerated carrier separation. The latter is critical in controlling the overall efficiency in one-step photoexcitation systems. In this study, a nanosized Bi0.6Y0.4VO4 solid solution was prepared by a coprecipitation method following with hydrothermal or calcination processes. The S-scheme heterojunction was fabricated by in-situ pressure-induced transformations of bismuth vanadate from the tetragonal zircon phase to the monoclinic scheelite phase, which led to the formation of BiVO4 nanoparticles with a diameter of approximately 5 nm on the surface of Bi0.6Y0.4VO4. Bi0.6Y0.4VO4 with S-scheme heterojunctions showed significantly enhanced photocatalytic overall water splitting activity compared with using bare Bi0.6Y0.4VO4. Characterization of the carrier dynamics demonstrated that a superior carrier separation through S-type heterojunctions might have caused the enhanced overall water splitting (OWS) activity. Surface photovoltage spectra and the results of selective photodeposition experiments indicated that the photogenerated holes mainly migrated to the BiVO4 nanoparticles in the heterojunction. This confirmed that the charge transfer route corresponds to an S-scheme rather than a type-II heterojunction mechanism under light illumination. This study presents a facile and efficient strategy to construct S-scheme heterojunctions through a pressure-induced phase transition. The results demonstrated that S-scheme junctions composed of different crystalline phases can boost the carrier separation capacity and eventually improve the photocatalytic OWS activity.

The solid solution photocatalyst plays a vital role in designing the one-step excitation water splitting system. However, the co-existence of the evolution of surface heterostructure together with the gradual formation of solid solutions makes it difficult to distinguish the inherent role of solid solution and surface structure in OWS reaction. Herein, Bi0.5Y0.5VO4 solid solution was synthesized through a fine-tuned co-precipitation procedure at room temperature, which acted as starting materials for further annealing treatment. Systematic characterizations revealed that variations in surface B-V-O domain at different temperatures induced the generation of particular heterogeneous structures in the solid solution surface. After annealing at 600 degrees C, the surface V-rich amorphous layer on Bi0.5Y0.5VO4 delivered functional electron trapping and optimized reaction dynamics, leading to enhanced OWS activity. In contrast, a nano-junction alignment formed at 800 degrees C near the surface resulted in an inappropriate band structure and poor charge dynamics, finally suppressing the OWS activity. (C) 2022 Elsevier Inc. All rights reserved.

Cobalt oxides find widespread application in energy materials as oxygen evolution catalysts (OECs) in the oxygen evolution reaction (OER) and photocatalytic overall water splitting (OWS) reaction. However, the nature of the active cobalt species, their role in these reactions, and possible commonalities remain poorly understand. Here, the impact of (redox-inert) germanium dopants on the physicochemical properties of Co3O4 nanoparticles was investigated in electrochemical oxygen evolution and photo-catalytic OWS reactions. A significant enhancement in OER performance on doping is attributed to the restructuring of spinel Co(3)O(4)to serpentine Co3Ge2(OH)(5), with the latter transforming to an oxyhydroxide active phase during OER. Combination of the p-type Co3Ge2(OH)(5) semiconductor as an OEC with an n-type Bi0.5Y0.5VO4 semiconductor doubles the photocatalytic OWS activity of the latter, resulting in H2 and O2 productivities of & SIM;175.7 and & SIM;90.1 smol/h, respectively. Formation of the composite semiconductor induces an intense internal electric field across the p-n junction, facilitating separation of photogenerated carriers and increased OWS activity, which is also validated in alternative photocatalyst, Al-doped SrTiO3. A similar transformation of serpentine Co3Ge2(OH)5 to an oxyhydroxide was not observed during OWS, indicating that Ge doping confers distinct advantages for electrochemical OER vs photocatalytic OWS.

The reconstruction during oxygen evolution reaction(OER)significantly affects the electronic and local geometry structure of metal sites in electrocatalyst.Compared with well-investigated cobalt-based mate-rials,the reconstruction of rocksalt CoO with purely Co2+in octahedral(Oh)coordination has not been revealed in detail.Herein,monolayer CoO supported on reduced graphene oxide(rGO)was synthesized via a one-pot hydrothermal strategy with calcinating in Ar atmosphere.The structure evolution of two-dimension(2D)CoO/rGO during OER was revealed by in situ X-ray absorption spectroscopy(XAS).The transition from CoO toward Co3O4 already occurred at open circuit potential,further enhanced at 1.23 V(vs.RHE).The CoOx(OH)y was determined as the active phase at 1.53 V,displaying a tetrahedral Co coordination defective spinel Co3O4 with the Co-O shell that featured the(oxy)hydroxide,not the stan-dard CoOOH.After OER,the irreversible transition from CoO to Co3O4 was observed.In contrast,in situ Raman spectra revealed a reversible amorphization process on Co3O4/rGO under operation conditions.Furthermore,this study indicated that the reconstruction behavior could be more effectively revealed by XAS using 2D materials.

In this work, BiVO4-based solid solutions, Bi0.5Y0.5VO4, were prepared via the MOF-derived method initially. The physical and chemical properties of the Bi0.5Y0.5VO4 samples were characterized by XRD, Raman spectra, XPS, HRTEM, element mapping, UV-vis DRS spectrum, TRPL and electrochemical analysis. The results showed that Y sources will be beneficial for the generation of tetragonal phase BiVO4, which made Bi0.5Y0.5VO4 samples constructed by tetragonal Bi0.5Y0.5VO4 and amorphous Bi0.5Y0.5VO4. The ratio of the tetragonal Bi0.5Y0.5VO4 was changed if the variation of the calcined time increased, which could be ascribed to the conversion of the amorphous Bi0.5Y0.5VO4. Consequently, photocatalytic overall water splitting property was enhanced and the results exhibited that Bi0.5Y0.5VO4-10 h samples exhibited the best performance with a rate of 124.2 mu mol H-2 and 61.7 mu mol O-2 per hour. The reason could be attributed to the variation of twisting degree, which thus influencing the internal electric field of the materials. More importantly, after metallic Pt particles as co-catalysts deposited, the ratio of H-2:O-2 was decreased. It could be proposed that the electric field shield effect will emerge to regulate the interfacial internal electric field further, which could play an essential role in the procedure of photocatalytic water splitting, especially for the reduction procedure.

采用纳米复刻(浇筑)法制备一系列介孔CuFe2O4.通过X射线衍射(XRD)、N2物理吸附、透射电镜(TEM)等研究了不同制备条件对有序介孔CuFe2O4结构形成的影响.研究发现，作为对比，柠檬酸法仅能合成普通的四方相CuFe2O4纳米颗粒，但是硬模板法则能合成出高温淬火才能形成的立方晶相介孔结构CuFe2O4.进一步研究了该催化剂同时催化去除碳烟和氮氧化合物(NOx)的性能，研究发现，与柠檬酸法合成的普通CuFe2O4催化剂相比，介孔结构CuFe2O4不仅大幅降低了碳烟起燃温度(324降低到278℃)，而且将N2的最高产率从5.9%提升到了92.2%.基于原位漫反射红外(in-situ DRIFTS)的机理分析研究表明，合成过程中采用NaOH除去硬模板的过程中会在介孔CuFe2O4表面造成大量残留的钠盐，这种高分散的钠物种促进了NOx的吸附并转化为硝酸盐物种，从而促进碳烟氧化以及NOx转化.但是与表面Na修饰的CuFe2O4相比，体相Na掺杂的CuFe2O4虽然具有更好的有序介孔结构，但是其氧化性能下降，进一步也导致了NOx的催化还原性能的下降.

Developing low-cost and high-efficient noble-metal-free cocatalysts has been a challenge to achieve economic hydrogen production. In this work, molybdenum oxides (MoO3−x) were in situ loaded on polymer carbon nitride (PCN) via a simple one-pot impregnation-calcination approach. Different from post-impregnation method, intimate coupling interface between high-dispersed ultra-small MoO3−x nanocrystal and PCN was successfully formed during the in situ growth process. The MoO3−x-PCN-X (X=1, 2, 3, 4) photocatalyst without noble platinum (Pt) finally exhibited enhanced photocatalytic hydrogen performance under visible light irradiation (λ>420 nm), with the highest hydrogen evolution rate of 15.6 µmol/h, which was more than 3 times that of bulk PCN. Detailed structure-performance revealed that such improvement in visible-light hydrogen production activity originated from the intimate interfacial interaction between high-dispersed ultra-small MoO3−x nanocrystal and polymer carbon nitride as well as efficient charge carriers transfer brought by Schottky junction formed.

Modifying photocatalyst with defects offers effective pathway to tailor light absorption properties, but may result in more sluggish kinetics. Therefore, enhanced light absorption often could not guarantee increased activity. Here, we report a dual defect strategy to extend light absorption with minimal loss in charge dynamics. Fine-tuned amount of dual defect, i.e., nitrogen defects and single-site copper, is simultaneously generated in polymer carbon nitride(PCN) through in-situ vapor diffusion method. Surface nitrogen defect extends the light absorption to long-wavelength via sub-band absorption. The interaction between nitrogen and single-site copper at certain concentration retains the charge dynamics by making the photogenerated electrons more delocalized through the newly-formed copper-nitrogen bonds. As a result, champion modified PCN exhibits robust hydrogen production activity, roughly 4.5-fold greater than the pristine counterpart in both visible and full light ranges. More intriguingly, this synergism provides PCN with efficient visible light activity even in faint tailing optical absorption region(>450 nm).

A novel nano-dodecahedron Bi0.5Y0.5VO4 solid solution with a diameter ranging from 20 to 50 nm has been prepared initially. The sample was characterized by XRD, SEM, HRTEM, element mapping, XPS, UV vis spectrum, Raman spectra, Mott-Schottky and XPS valence band analysis to reveal its properties. Photocatalytic experiment exhibited that H-Bi0.5Y0.5VO4 exhibited a much superior activity than the P-Bi0.5Y0.5VO4 among overall water splitting. The enhanced twisting degree in hetero-Bi0.5Y0.5VO4 (H-Bi0.5Y0.5VO4), which reconstructed the internal electric field and thus promoting the photogenerated carriers migrating directionally to form the direct Z-scheme heterojunction, should be responsible for the improvement of the photocatalytic performances. Furthermore, it also contributed to the morphology edge formation, which could be another critical factor for improving the photocarriers separation efficiency after simulating the rules of charge distribution. Additionally, results also indicated that the co-catalysts Rh@Rh2O3 could unlock a new charge transfer channel in the procedure of photocatalytic overall water splitting.

In this study, a ZnxCd1-xS solid solution was successfully synthesized using a hydrothermal method. MoS2 serving as a co-catalyst for hydrogen evolution was also prepared through a one-pot hydrothermal method. The structures, morphology, chemical states, and optical properties were characterized using powder X-ray diffraction, scanning electron microscopy, high-angle annular dark field-scanning transmission electron microscopy, elemental mapping, X-ray photoelectron spectroscopy, and UV-Vis diffuse reflection spectroscopy. Visible-light-driven photocatalytic experiments were conducted to simultaneously achieve hydrogen production and amoxicillin antibiotic wastewater degradation. The results indicated 8%MoS2/ZnxCd1-xS achieves the best photocatalytic performance. The ZnxCd1-xS samples illustrated a superior performance to that of CdS, which can be attributed to a thermodynamic improvement. Based on the results of PL and TRPL analyses, the enhancement of the hydrogen production mechanisms can be ascribed to the prolonged separation process of the photocarriers. Furthermore, the degradation results were analyzed using the HPLC method and the possible degradation pathways were determined through the HPLC-MS techniques.

Photocatalytic overall water splitting (OWS) in a stoichiometric ratio has attracted increasing attention for the realization of a sustainable, environmentally friendly future. However, this reaction exhibits sluggish kinetics due to efficiency limitations of the involved steps, including photon absorption, electron transfer, and the reactions that occur at triple-phase boundary regions. Herein, we report a general multiscale strategy to address this challenge by designing a model composite catalyst with a high loading density of isolated Bi0.5Y0.5VO4 nanocrystals, as building blocks, dispersed in a hexagonally ordered mesoporous silica matrix. In contrast to the well-recognized heterojunction formed between different semiconductors, we show that confined growth favours the formation of isolated quaternary solid-solution photocatalysts (Bi0.5Y0.5VO4), which can further interface with the insulating silica to overcome temperature limitations and exhibit enhanced photon absorption and electrochemical and mass transfer properties due to the transparent periodic porous structure of silica and the as-formed small nanocrystals with high crystallinity and a passivated surface. When the semiconductor photocatalyst is incorporated with the inert silica insulator, this nanoarchitecture does not inhibit the OWS activity but actually delivers a 10-fold higher OWS activity than bulk Bi0.5Y0.5VO4 prepared by the conventional solid-state method. (C) 2018 Elsevier Inc. All rights reserved.

通过浸渍法制备了一系列负载0.5％(重量百分比)Pd的氧化铈-氧化锆(NDK-84,由日本新日本电工株式会社提供)催化剂材料,并通过全面的表征手段,包括扫描电子显微镜(SEM)、透射电子显微镜(TEM)、高分辨透射电子显微镜(HR-TEM)、元素分布、X-射线衍射(XRD),氮气吸脱附测试与比表面积和孔径分布分析(BET)、X射线光电子能谱(XPS)等,研究了不同Pd前驱体和不同热老化处理条件、H2还原条件对Pd在铈锆固溶体上的分散、生长与烧结行为的影响,并评估了它们的三效催化活性.结果表明,热老化处理过程与还原过程显著影响了Pd在氧化物载体表面上的分散,因此导致不同的催化活性.

In this work, bismuth nanosphere doped polymeric carbon nitride (Bi/g-C3N4) was applied for photocatalytically converting antibiotic wastewater into hydrogen energy.