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The rational design of durable and nonprecious nanocomposite photocatalysts with efficient charge separation and abundant active sites is still a grand challenge for photocatalytic hydrogen production from water reduction. Herein, a novel ternary nanocomposite, MoO 2 decorated Mn 0.5 Cd 0.5 S/Cu 2 O p-n heterojunction has been constructed via a facile two-step route employing the energy band engineering theory. Impressively, the optimized ternary Mn 0.5 Cd 0.5 S/Cu 2 O/MoO 2 nanocomposite displays a robust photocatalytic H 2 -evolution rate of 733.24 μmol h−1 under simulated solar light irradiation, more 4.2 times higher than pure Mn 0.5 Cd 0.5 S. The results demonstrated that the p-n heterojunction formed between n-type Mn 0.5 Cd 0.5 S and p-type Cu 2 O could markedly promote the interfacial charge transfer/separation through the internal electric field, whereas the MoO 2 cocatalyst with low overpotential could effectively collect photoinduced electrons and dramatically facilitate the H 2 -evolution kinetics. Moreover, both Cu 2 O and MoO 2 could improve the light-harvesting ability of pristine Mn 0.5 Cd 0.5 S, further contributing to the boosted hydrogen generation activity. [Display omitted] • MoO 2 decorated Mn 0.5 Cd 0.5 S/Cu 2 O p-n heterojunction synthesized for H 2 -production. • Multichannel charge-carrier transfer between Mn 0.5 Cd 0.5 S, Cu 2 O and MoO 2 discussed. • High H 2 -production rate achieved over composite, 4.2 folds higher than Mn 0.5 Cd 0.5 S. [ABSTRACT FROM AUTHOR]

The construction of efficient semiconductor/cocatalyst heterojunction is a promising strategy to promote the photocatalytic H 2 -production efficiency from water reduction. Herein, a novel Cu 2 (OH) 2 CO 3 /Zn 0.5 Cd 0.5 S heterojunction composite with superior photocatalytic H 2 -generation activity and stability was prepared via a facile in situ synthetic route, in which Cu 2 (OH) 2 CO 3 served as cocatalyst stimulating the photocatalytic H 2 -evolution performance of Zn 0.5 Cd 0.5 S. The Cu 2 (OH) 2 CO 3 /Zn 0.5 Cd 0.5 S heterojunction photocatalyst containing 5 wt% of Cu 2 (OH) 2 CO 3 exhibited a prominent H 2 -evolution efficiency of 275.7 μmol h−1, which is superior to the noble metal Pt-modified Zn 0.5 Cd 0.5 S photocatalyst (237.3 μmol h−1) and much higher than bare Zn 0.5 Cd 0.5 S (90.8 μmol h−1). The active Cu+/Cu0 species generated during the photoreaction process is responsible for the prominent H 2 -production activity of the heterojunction photocatalyst, which plays triple roles in enhancing the photoactivity of Zn 0.5 Cd 0.5 S via accelerating the charge separation, decreasing the overpotential of H 2 -generation and improving the reduction ability of photoinduced electrons. Moreover, the formed Cu+/Cu0 species during photoreaction can be readily oxidized back to Cu 2 (OH) 2 CO 3 upon exposure to air, thus restores the photoactivity and therefore enables good reusability of the Cu 2 (OH) 2 CO 3 /Zn 0.5 Cd 0.5 S heterojunction photocatalysts. This work provides a new insight into the fabrication of Cu 2 (OH) 2 CO 3 -assisted heterojunction photocatalysts with the highly stable and efficient performances for solar-to-chemical energy conversion. Unlabelled Image • A novel binary Cu 2 (OH) 2 CO 3 /Zn 0.5 Cd 0.5 S composite was successfully synthesized. • The trifunctional roles of Cu 2 (OH) 2 CO 3 cocatalyst were discussed. • Mechanism of the enhanced photocatalytic activity was illuminated. [ABSTRACT FROM AUTHOR]

To conquer the disadvantage of low photocatalytic efficiency resulted from narrow photoresponse range and electron-hole recombination, a 2D nanoplate-like MoS 2 /Bi 2 WO 6 heterojunction photocatalyst was designed and prepared by a facile two-step hydrothermal technique. Compared with pure Bi 2 WO 6 , the MoS 2 / Bi 2 WO 6 composite displayed an enhanced photoabsorption in the whole visible light region. Through the photodegradation of rhodamine B (RhB) under visible light irradiation (λ>400 nm), the photocatalytic activities of the obtained products were evaluated and the MoS 2 /Bi 2 WO 6 composite exhibited higher photocatalytic performance than that of pure Bi 2 WO 6 . The enhanced photocatalytic performance was attributed to the broad photoabsorption and low charge recombination driven by the photogenerated potential difference formed at the MoS 2 /Bi 2 WO 6 heterojunction interface. [ABSTRACT FROM AUTHOR]

In this paper, novel TiO 2 /Bi 2 WO 6 heterojunction photocatalysts with hollow microsphere structures were successfully fabricated by a one-pot glucose-assisted hydrothermal route followed by the calcination at 450 °C. The photocatalytic activities of the as-prepared photocatalysts were evaluated on the degradation of rhodamine B (RhB) aqueous solution under visible light irradiation and the results indicated that the as-prepared TiO 2 /Bi 2 WO 6 composite exhibited higher photocatalytic activity than bare TiO 2 and Bi 2 WO 6 . In addition, the TiO 2 /Bi 2 WO 6 composite with TiO 2 loading of 20 wt.% showed the highest photocatalytic activity and retained the high photocatalytic performance after four recycles for the photodegradation of RhB, confirming its stability and practical usability. The enhanced photocatalytic activity of TiO 2 /Bi 2 WO 6 composite was attributed to well matched energy band positions of TiO 2 and Bi 2 WO 6 , which facilitated the efficient separation of photogenerated electron–hole pairs and thereby led to the increasing photocatalytic activity. On the basis of calculated energy band positions, the results of photoluminescence (PL) and active species trapping experiments, the mechanism of the obviously enhanced photocatalytic performance was proposed. [ABSTRACT FROM AUTHOR]

• Mn 0.5 Cd 0.5 S decorated with Au and MoO 2 dual cocatalysts synthesized for H 2 -production. • Synergetic effects between the multifunctional Au NPs and MoO 2 cocatalysts discussed. • High H 2 -production rate achieved over composite, 3.73 folds higher than Mn 0.5 Cd 0.5 S. The construction of semiconductor-based nanoheterostructures toward achieving high efficient solar-to-fuel conversion is greatly limited by the insufficient electron-hole separation and the narrow spectrum range of light absorption. In this work, a novel Mn 0.5 Cd 0.5 S solid solution decorated with robust and multifunctional MoO 2 and Au nanoparticles (NPs) has been constructed by a facile two-step route: the deposition of Au NPs via an in situ deposition route and further loading of MoO 2 via an ultrasonic chemical method. Characterization results show that both MoO 2 and Au NPs can be employed as efficient cocatalytic materials to significantly promote the H 2 -production over Mn 0.5 Cd 0.5 S semiconductor. Particularly, the ternary 2MoO 2 /3Au/Mn 0.5 Cd 0.5 S nanocomposite containing 3 wt% Au NPs and 2 wt% MoO 2 exhibited the optimum H 2 -production activity (638.83 µmol h−1) under simulated sunlight conditions, more 3.73-, 1.74- and 1.35-fold enhancement relative to pristine Mn 0.5 Cd 0.5 S, binary 3Au/Mn 0.5 Cd 0.5 S and 2MoO 2 /Mn 0.5 Cd 0.5 S, respectively. Mechanistic characterizations demonstrate that the positive synergetic effects between Au NPs and MoO 2 can simultaneously boost the light absorption capacities, the separation efficiency of the interfacial charge carriers, and the thermodynamic performances of the hydrogen evolution reaction by strengthening the reduction ability of the photogenerated electrons and lowering the hydrogen evolution overpotential, which integratively resulted in the boosted photoactivity. [ABSTRACT FROM AUTHOR]

• Au decorated S-scheme Mn 0.5 Cd 0.5 S/WO 3 composite synthesized for H 2 -production. • Mechanism of charge transfer and separation in Au decorated S-scheme discussed. • High H 2 -production rate achieved over composite, 2.74 folds higher than Mn 0.5 Cd 0.5 S. Spontaneously solar-driven H 2 -production from water reduction provides a promising strategy to solve the aggravating energy and environment crises worldwide, but it is severely limited by the rapid charge-carrier recombination and the slashing redox potentials requirement. Here, a new ternary Mn 0.5 Cd 0.5 S/WO 3 /Au heterostructure photocatalyst has been designed by chemical deposition of Au nanoparticles (NPs) on Mn 0.5 Cd 0.5 S/WO 3 step-scheme (S-scheme) composite matrix to boost the photocatalytic activity through the multichannel-enhanced charge transfer/separation. By optimizing the constituent of the heterostructure photocatalyst, the prepared Mn 0.5 Cd 0.5 S/WO 3 /Au photocatalyst with 30 wt% of WO 3 and 4 wt% of Au exhibits the highest H 2 -evolution rate of 517.13 µmol h−1 under simulated solar light irradiation, more 2.74, 1.63 and 1.45 times higher than bare Mn 0.5 Cd 0.5 S and Mn 0.5 Cd 0.5 S loaded with WO 3 and Au alone, respectively. Mechanistic characterizations and control experiments have revealed that the S-scheme charge transfer in Mn 0.5 Cd 0.5 S/WO 3 heterojunction together with the "electron reservoir" resulting from the Au NPs contribute to the superior H 2 -generation activity over Mn 0.5 Cd 0.5 S/WO 3 /Au catalyst, which not only dramatically promotes the charge-carrier separation but also remains the strong redox ability of photoinduced electrons and holes in such photocatalytic system. [ABSTRACT FROM AUTHOR]

[Display omitted] Developing cost-effective cocatalyst-modified photocatalytic systems with boosted carrier separation and rapid surface catalytic reaction is an ideal strategy for effectively converting solar energy into desired fuels. Herein, a series of Cu 7 S 4 /Mn 0.3 Cd 0.7 S hierarchical heterostructures are designed and fabricated to achieve efficient and robust photocatalytic H 2 evolution by coupling one-dimensional (1D) Mn 0.3 Cd 0.7 S nanorods with two-dimensional (2D) Cu 7 S 4 nanosheets through a facile sonochemical strategy. Benefiting from dimensionality and cocatalyst effects, the constructed 2D/1D Cu 7 S 4 /Mn 0.3 Cd 0.7 S heterojunction photocatalyst containing 1.5 wt% Cu 7 S 4 displays excellent photostability and superior photocatalytic H 2 evolution rate up to 914.3 μmol h−1, which is 4.43 and 2.22-folds increment relative to bare Mn 0.3 Cd 0.7 S and the 3 wt% Pt/Mn 0.3 Cd 0.7 S, respectively. The various characterization results reveal that the utilization of semimetallic Cu 7 S 4 nanosheets as the cocatalyst to form a Schottky heterojunction can promote the light-harvesting capability, suppress charge carrier recombination, and provide sufficient reaction sites for hydrogen generation, thereby resulting in the dramatically improved photocatalytic performance. This work clarifies the role of Cu 7 S 4 nanosheets as the robust and cost-effective cocatalyst in the photocatalytic reaction and opens a new horizon for designing other Cu 7 S 4 -based cocatalyst/semiconductor Schottky heterostructures for efficient solar-to-fuel conversion. [ABSTRACT FROM AUTHOR]

For the 63NiO-Si heterojunction betavoltaic nuclear battery, the energy deposition of the energy conversion material itself was simulated by Monte Carlo simulation, and the structure of the 63NiO-Si heterojunction was optimized based on the theoretical calculation results. When the thickness of 63NiO is 4 μm and the doping concentration of Si is 1 × 1015 cm−3, the short-circuit current density, open-circuit voltage, fill factor, and maximum output power density of the nuclear battery are 1.22 μA · cm−2, 3.17 V, 0.95, 3.67 μW · cm−2. In addition, the output performance of 63Ni/NiO-Si heterojunction betavoltaic nuclear cell was calculated in this study. Under the condition that the activity of the radioactive source and the thickness of NiO(63NiO) are the same in the two structures, the proposed structure (63NiO-Si) has greatly improved the output performance of the nuclear battery by reducing the energy lost from radioactive source self-absorption. [ABSTRACT FROM AUTHOR]

[Display omitted] • Direct Z-scheme Mn 0.5 Cd 0.5 S/CoTiO 3 heterojunction was designed. • Mechanism for the enhanced photoactivity over Mn 0.5 Cd 0.5 S/CoTiO 3 heterojunction discussed. • High ammonia production rate achieved over heterojunction, 5.1-fold higher than Mn 0.5 Cd 0.5 S. The exploration and design of highly efficient and robust photocatalysts composed of earth-abundant materials for ambient photocatalytic N 2 fixation to ammonia remains a significant challenge. Here, we have fabricated a stable and highly efficient direct Z-scheme Mn 0.5 Cd 0.5 S/CoTiO 3 heterostructure for N 2 fixation by depositing Mn 0.5 Cd 0.5 S nanoparticles on CoTiO 3 surface. Under ambient conditions, the optimized Mn 0.5 Cd 0.5 S/CoTiO 3 heterojunction achieved a significant NH 3 production rate of 121.9 μmol g-1h−1 without cocatalyst modification, representing a 5.1- and 5.9-fold increase over pristine Mn 0.5 Cd 0.5 S and CoTiO 3 , respectively, and also exceeding most previously reported photocatalytic systems. The significant improvement in ammonia production primarily results from the Z-scheme charge transfer path between the Mn 0.5 Cd 0.5 S and CoTiO 3 components, which enables effective separation of photoinduced carriers while maintaining their robust redox capacity, thus dramatically boosting ammonia generation performance. This research may provide new insights for advancing other alternative Z-scheme photocatalytic systems with remarkable stability and exceptional efficiency in N 2 fixation. [ABSTRACT FROM AUTHOR]

The rational design of hierarchical heterojunction photocatalysts with efficient spatial charge separation remains an intense challenge in hydrogen generation from photocatalytic water splitting. Herein, a noble-metal-free MoS 2 /g-C 3 N 4 /ZnIn 2 S 4 ternary heterostructure with a hierarchical flower-like architecture was developed by in situ growth of 3D flower-like ZnIn 2 S 4 nanospheres on 2D MoS 2 and 2D g-C 3 N 4 nanosheets. Benefiting from the favorable 2D-2D-3D hierarchical heterojunction structure, the resultant MoS 2 /g-C 3 N 4 /ZnIn 2 S 4 nanocomposite loaded with 3 wt% g-C 3 N 4 and 1.5 wt% MoS 2 displayed the optimal hydrogen evolution activity (6291 μmol g−1 h−1), which was a 6.96-fold and 2.54-fold enhancement compared to bare ZnIn 2 S 4 and binary g-C 3 N 4 /ZnIn 2 S 4 , respectively. Structural characterizations reveal that the significantly boosted photoactivity is closely associated with the multichannel charge transfer among ZnIn 2 S 4 , MoS 2 , and g-C 3 N 4 components with suitable band-edge alignments in the composites, where the photogenerated electrons migrate from g-C 3 N 4 to ZnIn 2 S 4 and MoS 2 through the intimate heterojunction interfaces, thus enabling efficient electron-hole separation and high photoactivity for hydrogen evolution. In addition, the introduction of MoS 2 nanosheets highly benefits the improved light-harvesting capacity and the reduced H 2 -evolution overpotential, further promoting the photocatalytic H 2 -evolution performance. Moreover, the MoS 2 /g-C 3 N 4 /ZnIn 2 S 4 ternary heterostructure possesses prominent stability during the photoreaction process owing to the migration of photoinduced holes from ZnIn 2 S 4 to g-C 3 N 4 , which is deemed to be central to practical applications in solar hydrogen production. [ABSTRACT FROM AUTHOR]

In this work, energy converters, which contain a GaP–Si heterojunction and Si-based Schottky barrier diodes with Al, Ti, Ag, and W, are used to convert 2 μm-thick 63Ni radioactive source energy into electrical energy. First, energy deposition distributions of the 63Ni radioactive source in these converters are simulated by using the Monte Carlo method. Then, the electrical output properties of the 63Ni/GaP–Si cell and 63Ni/metal–Si cell are determined through the numerical calculation. For the 63Ni/GaP–Si cell, with the optimized thickness of the GaP layer and doping concentration of Si, the maximum output power density and the conversion efficiency are 0.189 µW cm−2 and 1.83%, respectively. For the Si-based Schottky barrier cells with Al, Ti, Ag, and W, the 63Ni/Al–Si cell has the best electrical output properties with the same thickness of the metal layer and doping concentration of Si. When the thickness of metal Al is 0.1 µm and the doping concentration Na is 1 × 1013 cm−3, the maximum output power density and the conversion efficiency are 0.121 µW cm−2 and 1.18%, respectively. The calculation results indicate that the 63Ni/GaP–Si battery has better electrical output properties than the 63Ni/Al–Si Schottky battery. These results are valuable for fabricating practical batteries. [ABSTRACT FROM AUTHOR]

Exploring efficient and robust photocatalysts for solar hydrogen generation from water reduction is great significant in solving the energy shortage and environment contamination simultaneously. Herein, benefiting from the matchable energy band structures and band bending, the direct Z-scheme ZnIn 2 S 4 /NiWO 4 heterojunctions were successfully constructed by anchoring p-type NiWO 4 nanoparticles onto n-type ZnIn 2 S 4 nanosheets through a facile sonochemical route. By carefully regulating the interfacial structure, the optimized ZnIn 2 S 4 /NiWO 4 heterostructure without any cocatalyst displays excellent stability and remarkably improved photocatalytic hydrogen evolution activity (16.3 mmol∙g−1∙h−1), more 3.57-folds increment than bare ZnIn 2 S 4 photocatalyst. Mechanistic characterizations demonstrate that the dramatically boosted photocatalytic performance mainly results from the constructed Z-scheme heterostructure and intimately interfacial contact between ZnIn 2 S 4 and NiWO 4 , which results in the valid interfacial charge transfer channels, powerful redox potential and reduced hydrogen evolution energy barrier, as confirmed by the joint analysis of electron spin resonance (ESR) and photoelectrochemical measurements. More importantly, the photoinduced holes of ZnIn 2 S 4 are rapidly and effectively consumed in the unique Z-scheme charge transfer channels, which greatly favors the suppression of the photocorrosion caused by insufficient hole extraction during the photocatalytic reaction, thereby promoting the overall stability and reusability of the ZnIn 2 S 4 /NiWO 4 composite photocatalyst. This study paves the way for constructing other Z-scheme nano-heterostructure consisting of p-type and n-type semiconductors with efficient photoactivity and robust stability for energy and environmental applications. [Display omitted] • Z-scheme heterojunction consisting of p-type and n-type semiconductors was designed. • Mechanism for the enhanced photoactivity over ZnIn 2 S 4 /NiWO 4 heterojunction discussed. • High H 2 -production rate achieved over heterojunction, 3.57-fold higher than ZnIn 2 S 4. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ternary Mn 0.5 Cd 0.5 S/CB/CuS hierarchical multiheterojunction system was designed. • Synergetic effect between multifunctional CB and CuS dual cocatalysts discussed. • High H 2 -production rate achieved over composite, 4.79-fold higher than Mn 0.5 Cd 0.5 S. Developing exceptionally robust and cost-effective cocatalysts to suppress charge recombination and reduce the reaction energy barrier remains an enormous challenge for producing high-valued and storable hydrogen fuel from photocatalytic water splitting. Herein, novel Mn 0.5 Cd 0.5 S nanoparticles modified with multifunctional carbon black (CB) nanowires and CuS nanotubes as dual cocatalysts were fabricated via sonochemical loading, and subsequent in-situ deposition routes. In this ternary hierarchical architecture, both CB nanowires and CuS nanotubes can serve as normal electron cocatalysts to markedly promote the hydrogen generation performance by lowering the thermodynamic overpotential for hydrogen evolution. Moreover, due to the high electrical conductivity, the multifunctional CB material can also function as a bridge to effectively capture and transmit the photoexcited electrons from Mn 0.5 Cd 0.5 S to CuS with outstanding electrocatalytic hydrogen evolution activity, thus maximizing the carrier separation and H 2 -evolution reaction kinetics. Interestingly, the cooperative effects between CB and CuS dual cocatalysts are also helpful for improving the oxidation capacity of photoexcited holes by lowering the valence band position of Mn 0.5 Cd 0.5 S, which further accelerates the electron-hole separation. As a result, the constructed Mn 0.5 Cd 0.5 S/CB/CuS hierarchical multiheterojunction catalyst shows the superior hydrogen generation efficiency of 819.9 μmol h−1 and excellent stability under simulated solar light irradiation. [ABSTRACT FROM AUTHOR]