Highest Hydrogen Evolution Rate Research Articles

Self-modified breaking hydrogen bonds to highly crystalline graphitic carbon nitrides nanosheets for drastically enhanced hydrogen production

Highly crystalline graphitic carbon nitride (g-C3N4) possesses the high separation efficiency of photogenerated electron-hole pairs owing to the significantly decreased intralayer hydrogen bonds, which leads to drastic improvement of photocatalytic activity. However, the preparation of such g-C3N4 material remains a challenge by a simple and economic thermal-treatment in a furnace. Herein, we report a novel and effective strategy for high-yield synthesis of extremely active crystalline carbon nitride nanosheets (CCNNSs) by two-step calcination without the assistance of any additive or salt intercalation. As expected, the as-prepared CCNNSs exhibit a remarkably high hydrogen evolution rate of 9577.6 μmol h−1 g−1 under simulated solar light irradiation, which is 15.5 times than that of bulk g-C3N4, as well as higher than most of the reported crystalline g-C3N4. Moreover, a highly apparent quantum efficiency of 9.01% at 420 nm for hydrogen evolution can be achieved, which is also superior to the reported crystalline g-C3N4. Such two-step calcination approach not only provides an economical way to effectively regulate the crystallinity of bulk g-C3N4, but also achieves the preparation of CCNNSs with high yield. Our research opens up a new window to self-modification and fabrication of highly active metal-free photocatalysts for solar light-driven hydrogen production.

Rational construction of multiple interfaces in ternary heterostructure for efficient spatial separation and transfer of photogenerated carriers in the application of photocatalytic hydrogen evolution

The design of efficient and stable photocatalyst plays a critical role in the photocatalytic hydrogen evolution from water splitting. Herein, we develop a novel ZnS/CdS/ZnO ternary heterostructure by the in-situ sulfuration of CdS/ZnO, which includes four contact interfaces: CdS-ZnS interface, ZnS-ZnO interface, CdS-ZnO interface and ZnS-CdS-ZnO ternary interface, forming three charge carrier-transfer modes (type-I, type-II and direct Z-scheme) through five carrier-transfer pathways. As a result, the separation and transfer of photoexcited electron-hole pairs are promoted significantly, resulting in a high hydrogen evolution rate of 44.70 mmol h−1 g−1, which is 2, 3.7 and 8 times higher than those of binary heterostructures, CdS/ZnO, CdS/ZnS and ZnS/ZnO, respectively, and 26.5, 280 and 298 times higher than those of single CdS, ZnO and ZnS, respectively. As a counterpart ternary heterostructure, CdS/ZnS/ZnO contains only two interfaces: CdS-ZnS interface and ZnS-ZnO interface, which form two charge carrier-transfer modes (type-I and type-II) through two carrier-transfer pathways, leading to its much lower hydrogen evolution rate (27.25 mmol h−1 g−1) than ZnS/CdS/ZnO ternary heterostructure. This work is relevant for understanding the charge-transfer pathways between multi-interfaces in multicomponent heterojunctions.

Hierarchical Nanotubular Anatase/Rutile/TiO2(B) Heterophase Junction with Oxygen Vacancies for Enhanced Photocatalytic H2 Production.

Oxygen vacancies have been demonstrated to enhance the interfacial charge separation in TiO2-based photocatalysts. In this report, we explored a facile route to synthesize hierarchical nanotubular anatase/rutile/TiO2(B) nanostructures with high surface area and defective electronic structure. The formation of oxygen vacancies in the heterophase junction was analyzed by UV-vis absorption spectra, electron spin resonance, and X-ray photoelectron spectroscopy. The enhanced interfacial charge separation and transportation ensured the excellent photoactivity of oxygen-deficient junctions for the photocatalytic production of hydrogen. As a result, the defective anatase/rutile/TiO2(B) junction showed a high hydrogen evolution rate of 2.79 mmol/h, which was 19 times higher than blank TiO2 nanotubes. The results demonstrate that defect modulation is a powerful tool to enhance the catalytic performances of TiO2-based photocatalysts.

Porous defect-modified graphitic carbon nitride via a facile one-step approach with significantly enhanced photocatalytic hydrogen evolution under visible light irradiation

Graphitic carbon nitride (g-C3N4) has been considered as one of the most promising photocatalysts for solar energy conversion. However, the intrinsic drawbacks of insufficient visible-light absorption and poor charge separation efficiency seriously limit its practical applications in visible light photocatalytic hydrogen evolution. In this work, a facile one-step strategy was proposed to construct a novel porous defect-modified graphitic carbon nitride (P-DCN) via thermal polymerization of a freeze-dried crystalline mixture containing dicyandiamide (DCDA) and ammonium chloride (NH4Cl) under nitrogen atmosphere, in which both porous feature and two types of defects (cyano group and nitrogen vacancy) were simultaneously introduced into g-C3N4 framework. Results show that the as-synthesized P-DCN Exhibits 26 times higher hydrogen evolution rate (HER) under visible light irradiation than bulk g-C3N4, reaching 20.9 μmol h−1. In combination of porous and defective characteristics, P-DCN even demonstrates 2.0 and 1.8 folds higher HER than highly active porous graphitic carbon nitride (P-CN) and defect-modified g-C3N4 (DCN), respectively. The outstanding photocatalytic performance for hydrogen production originates from the remarkably improved visible light harvesting capability, the notably promoted separation and recombination inhibition of photoinduced charge carriers, and the increased amount of active sites and the strengthened mass transfer resulting from the combination effect of the porous feature, as-formed defects, and the enlarged specific surface area. Moreover, this approach could render a new insight for designing highly efficient visible light photocatalysts for the other transformations including CO2 reduction, environmental remediation, and organic synthesis process.

Enhanced photocatalytic H2-production activity of C-dots modified g-C3N4/TiO2 nanosheets composites

As a new carbon-based material, carbon dots (C-dots) have got widely preference because of its excellent electronic transfer capability. In this work, a novel ternary layered C-dots/g-C3N4/TiO2 nanosheets (CGT) composite photocatalysts were prepared by impregnation precipitation methods. The optimal ternary CGT composite samples revealed high photocatalytic hydrogen evolution rate in triethanolamine aqueous solutions, which exceeded the rate of the optimal g-C3N4/TiO2 composite sample by a factor of 5 times. The improved photocatalytic activity is owed to the positive effects of C-dots and layered heterojunction structure of TiO2 nanosheets and g-C3N4 sheets. C-dots in the CGT composites can serve as electron reservoirs to capture the photo-induced electrons. The well-defined layered heterojunction structure of CGT provides the intimate contact and the strong interaction of anatase TiO2 nanosheets and g-C3N4 sheets via face-to-face orientation, which restrains the recombination of photogenerated charge carriers, and thus enhances the photocatalytic H2-production activity. Electron paramagnetic resonance and transient photocurrent response proved the strong interaction and improved interfacial charge transfer of TiO2 nanosheets and g-C3N4 sheets, respectively. The mechanism of improving the photocatalytic H2-evolution activity was further confirmed by time-resolved fluorescence, electron paramagnetic resonance, transient photocurrent response and electrochemical impedance spectroscopy.

Factors influencing algal photobiohydrogen production in algal-bacterial co-cultures

Algal-bacterial co-cultures represent an alternative way for algal biohydrogen generation. Efficient algal hydrogen production requires anaerobiosis and electrons accessible for the algal FeFe‑hydrogenases. A number of factors strongly influence the development of this optimal environment. Various algal strains were tested for hydrogen evolution with a selected bacterial partner, a fully hydrogenase deficient Escherichia coli. During the hunt for the most efficient algae strains, gas-to-liquid phase ratio, algal optical density and algal cell size were identified as crucial factors influencing algal hydrogen evolution rate, accumulated algal hydrogen yield, carbon dioxide and oxygen levels as well as acetic acid consumption in illuminated algal-bacterial cultures. The highest accumulated hydrogen yields were observed for the different algal partners under similar experimental setup. The combination of a gas-to-liquid phase ratio of 1/1 with an algae cell density of 3.96∗108 algae cellml−1 (OD750: 1) resulted in the highest accumulated algal hydrogen yields under continuous illumination of ~50μmolm−2s−1 light at 25°C irrespective of the applied algae strain. Accumulated hydrogen yield was also strongly influenced by the algal cell size, smaller cell size correlated with higher hydrogen evolution rate. The highest accumulated algal hydrogen yield (88.98±2.19mlH2l−1d−1) was obtained with Chlorella sp. MACC 360 -E. coli ΔhypF co-culture.

Titania Gold Composite: Effect of Illumination on Size of Gold Nanoparticles with Consequent Implication on Photocatalytic Water Splitting

This work deals with the study of photodeposition (PD) of gold nanoparticles (AuNPs) on TiO2 by using different illumination sources, Medium pressure Mercury lamp (ML), Solar Simulator equipped with AM 1.5 (SL) and Tungsten lamp (WL). Different particle size of AuNPs on TiO2 were obtained by photodeposition method under different illumination sources, which clearly proves the influence of light source on the synthesis of Au–TiO2. The plasmonic activity of Au–TiO2 photocatalyst for water splitting reaction was observed to be strongly influenced by the particle size of Au as well as illumination source. Amongst the three different illumination sources used, smallest particle size for AuNP–TiO2 were observed under ML followed by SL and WL, as revealed by TEM analysis. Different illumination sources were also investigated to evaluate the activity of Au–TiO2 samples thus prepared under different illumination conditions. The order of hydrogen evolution rate (HER) observed for Au–TiO2 with different source of illuminations is ML > SL > WL. The highest HER of 1709 μmol/h was observed for Au–TiO2, which was synthesized and evaluated under ML irradiation. This may be explained on the basis of reduced catalytic activity and photothermal effect of Au nanoparticles with increasing particle size.

Electroplated Ni-Cu nanocrystalline alloys and their electrocatalytic activity for hydrogen generation using alkaline solutions

Hydrogen can be significantly considered the sustainable fuel for the energy storage and conversion. In this work, we synthesize nanocrystalline Ni-Cu alloys across the range of compositions and show that Ni-Cu alloys are indeed more active than pure nickel for hydrogen evolution reactions. The electroplated Ni-Cu alloy were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction, XRD, and energy dispersive X-ray, EDX. The HER was studied at electroplated Ni-Cu alloys in 1.0 M KOH solution at 298 K. The electroplated Ni-Cu alloys were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and polarization measurements to determine their electrocatalytic activity for the HER. The use of the appropriate concentrations of the addition agent simultaneously with the ultrasound waves during sample preparation was found to produce nanocrystalline Ni-Cu alloys. XRD patterns show that the Ni-Cu alloys possess the face centered cubic structure. The incorporation of Cu into the Ni alloys causes surface modification, which catalyzes the hydrogen evolution reaction (HER). The electroplated Ni-Cu alloy with ≈49 at% Cu contents shows the highest rate of hydrogen evolution. The increase of the Cu content more than ≈50 at% was accompanied by a decrease in the rate of HER.

Enhanced photocatalytic hydrogen evolution performance of mesoporous graphitic carbon nitride co-doped with potassium and iodine

The potassium and iodine co-doping combined with a mesoporous structure for developing a novel g-C3N4-based photocatalyst is constructed. The K and I co-doped mesoporous g-C3N4 has been successfully synthesized via the one pot thermal polymerization of a mixture consisting of dicyandiamide, KI, and SBA-15 used as the hard template. It is shown that this photocatalyst consists of short rod-like network with plenty of pores openings into their surfaces. The mesoporous structure and the doping with K and I in it have been verified by several techniques. For this photocatalyst, a blue shift of the optical absorption band edge induced by the mesoporous structure is compensated for by the red shift originated from the co-doping with K and I. This photocatalyst exhibits the longest life time of carries, the fastest charge transport, and the highest photocurrent density as compared with the mesoporous g-C3N4 and the K and I co-doped one. It is revealed a synergistic effect between the formation of the mesoporous structure and the co-doping with K and I. The synergistic effect make the K and I co-doped mesoporous g-C3N4 photocatalyst achieves a high hydrogen evolution rate of 80.58μmol/h, 9.7 times as high as that for pristine g-C3N4. These results may shed light on the integration of different modification strategies for developing novel g-C3N4-based photocatalysts with much enhanced photocatalytic activity.

Coupling of Crumpled-Type Novel MoS2 with CeO2 Nanoparticles: A Noble-Metal-Free p-n Heterojunction Composite for Visible Light Photocatalytic H2 Production.

In terms of solar hydrogen production, semiconductor-based photocatalysts via p–n heterojunctions play a key role in enhancing future hydrogen reservoir. The present work focuses on the successful synthesis and characterization of a novel p-MoS2/n-CeO2 heterojunction photocatalyst for excellent performance toward solar hydrogen production. The synthesis involves a simple in situ hydrothermal process by varying the wt % of MoS2. The various characterization techniques support the uniform distribution of CeO2 on the surface of crumpled MoS2 nanosheets, and the formation of p–n heterojunction is further confirmed by transmission electron microscopy and Mott–Schottky analysis. Throughout the experiment, it is demonstrated that 2 wt % MoS2 in the MoS2/CeO2 heterojunction photocatalyst exhibits the highest rate of hydrogen evolution with a photocurrent density of 721 μA cm–2. The enhanced photocatalytic activity is ascribed to the formation of the p–n heterojunction that provides an internal electric field to facilitate the photogenerated charge separation and transfer.

Formation of hybrid nanostructures comprising perovskite (Ba5Nb4O15)-MoS2 ultrathin nanosheets on CdS nanorods: Toward enhanced solar-driven H2 production

Solar-driven semiconductor-catalyzed photocatalytic water splitting is an important and eco-friendly chemical technique for the production of clean hydrogen fuel. However, a cost-effective, efficient photocatalyst with perfect photon-to-hydrogen molecule conversion remains elusive. Novel, noble-metal-free hybrid nanostructures comprising perovskite (Ba5Nb4O15)-MoS2 ultrathin nanosheets on CdS nanorods, with efficient photo-charge separation and migration capability for efficient solar-driven hydrogen production are designed. The nano-hybrid structures display a high hydrogen production rate of 147mmol·g–1·h–1 in the presence of lactic acid as a sacrificial electron donor under simulated solar irradiation; this value is much higher than those of the CdS/MoS2 (124mmol·g–1·h–1) and CdS/Ba5Nb4O15 (18mmol·g–1·h–1) nanostructures and that of the expensive CdS/Pt benchmark catalyst (34.98mmol·g–1·h–1). The apparent quantum yield at 425nm reaches to 28.2% in 5h. Furthermore, the rate of solar-driven hydrogen evolution in the presence of the ultrathin perovskite Ba5Nb4O15/MoS2 nanohybrid on the CdS nanorods is much faster than that of several noble-metal-free co-catalyst-modified CdS nanostructures reported earlier. UV–Vis absorption, photoluminescence, photocurrent, and impedance analyses of CdS@Ba5Nb4O15/MoS2 reveal that the high photocatalytic hydrogen evolution rate may due to the comparatively higher solar light-harvesting capacity and efficient charge separation and migration, which reduces the recombination rate. We anticipate that the presented design strategy for the development of noble metal-free catalysts combining perovskite and semiconductor nanostructures stimulate the development of diverse non-precious robust solar light-harvesting noble-metal-free materials for water splitting to satisfy the growing global energy demand.

Preparation of Carbon-Rich g-C3 N4 Nanosheets with Enhanced Visible Light Utilization for Efficient Photocatalytic Hydrogen Production.

Exfoliation of layered bulk g-C3 N4 (CNB) to thin g-C3 N4 sheets in nanodomains has attracted much attention in photocatalysis because of the intriguing properties of nanoscaled g-C3 N4 . This study shows that carbon-rich g-C3 N4 nanosheets (CNSC) can be easily prepared by self-modification of polymeric melon units through successively thermally treating bulk g-C3 N4 in an air and N2 atmosphere. The prepared CNSC not only retain the outstanding properties of nanosheets, such as large surface area, high aspect ratios, and short charges diffusion distance, but also overcome the drawback of enlarged bandgap caused by the quantum size effect, resulting in an enhanced utilization of visible light and photoinduced electron delocalization ability. Therefore, the as-prepared CNSC show a high hydrogen evolution rate of 39.6 µmol h-1 with a turnover number of 24.98 in 1 h at λ > 400 nm. Under irradiation by longer wavelength of light (λ > 420 nm), CNSC still exhibit a superior hydrogen evolution rate, which is 72.9 and 5.4 times higher than that of bulk g-C3 N4 and g-C3 N4 nanosheets, respectively.

Photocatalytic hydrogen production using Me/Cd0.3Zn0.7S (Me = Au, Pt, Pd) catalysts: Transformation of the metallic catalyst under the action of the reaction medium

The activity and stability of Me/Cd0.3Zn0.7S (Me = Au, Pt, Pd) photocatalysts in the course of hydrogen production from water under the action of visible radiation have been investigated. The mechanism of activation and deactivation of the catalysts have been elucidated for the first time using X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. An increase in the hydrogen evolution rate is observed for all of the catalysts at the early stages of testing. The highest hydrogen evolution rate, 5.4 μmol/min, is afforded by the 1%Pt/Cd0.3Zn0.7S catalyst. The activity of the Au/Cd0.3Zn0.7S and Pt/Cd0.3Zn0.7S catalysts becomes constant 7.5–9 h after the beginning of the photocatalytic test, while in the case of Pd/Cd0.3Zn0.7S the hydrogen evolution rate increases over the initial 6 h and then decreases. These specific features of the catalysts likely correlate with the initial state of the metals on the support surface. In particular, supported palladium is in the form of PdO, while gold and platinum are in the metallic state. The Au/Cd0.3Zn0.7S and Pt/Cd0.3Zn0.7S photocatalysts are activated due to metal encapsulation; the 1%Pd/Cd0.3Zn0.7S catalyst, due to the partial reduction of PdO to PdO x . The 1%Pd/Cd0.3Zn0.7S catalyst is deactivated because of the aggregation of nanoparticles of the cadmium sulfide–zinc sulfide solid solution.

Phosphorous doped graphitic-C3N4 hierarchical architecture for hydrogen production from water under visible light

Enriched macro/mesoporous graphitic-C3N4 (g-C3N4) micro-rods (CNRs) are prepared by direct calcination of reflux treated ethylene diphosphonic acid-melamine complex fiber network. The optimized phosphorous doped CNRs (P-CNRs) exhibit a high hydrogen-evolution rate of 4960 μmol h−1 g−1 (5.5 times that of pristine g-C3N4) with a remarkable recycling stability. The significantly enhanced performance is found to be attributed to the intentionally designed morphology and electronic properties of P-CNRs. This distinctive hierarchical architecture of CNRs enhances the light scattering, and provides a high specific surface area and thus more catalytically active sites. The P doping of g-C3N4 greatly increases the visible light absorption, narrows the band gap. It also results in a boost in the density state of the conduction band as revealed by the electron paramagnetic resonance (EPR) spectra. The strong visible light emission quenching, observed from the photoluminescence of P-CNRs and photocurrent measurements, implies an enhanced charge transfer/separation process. This work presents a very simple and direct method of designing and developing high-performance visible light driven catalysts for hydrogen production.

Ternary CdS/Au/3DOM-SrTiO3 composites with synergistic enhancement for hydrogen production from visible-light photocatalytic water splitting

New ternary composites based on three dimensionally ordered macroporous (3DOM) SrTiO3 (CdS/Au/3DOM-SrTiO3) were prepared and used as photocatalysts in visible light (λ>420nm) photocatalytic water splitting for hydrogen evolution. Through optimizing the pore size of 3DOM-SrTiO3 materials and the loading amounts of Au and CdS, CdS/Au/3DOM-SrTiO3(300), templated by 300nm sized poly(methyl methacrylate) colloids, was found to exhibit a remarkably enhanced photocatalytic hydrogen evolution rate (2.74mmol/h⋅g), which was 3.2 times as high as that of CdS/Au/C-SrTiO3 catalyst based on commercial SrTiO3. This notably enhanced photocatalytic performance was mainly attributed to the slow photon enhancement effect of 3DOM-SrTiO3(300) material, which significantly promoted the light harvesting efficiency of ternary composite for the slow photon region of 3DOM-SrTiO3(300) was well matched with the optical absorption band of photocatalyst. Further depositing Pt nanoparticles on CdS/Au/3DOM-SrTiO3(300) composite as a co-catalyst, an extraordinarily high hydrogen evolution rate (up to 5.46mmol/g⋅h) and apparent quantum efficiency (42.2% at 420nm) were achieved because of the synergistic effect of efficient carrier separation, Au SPR effect, and slow photon effect. Furthermore, these ternary CdS/Au/3DOM-SrTiO3 composite photocatalysts were very stable and could be easily recycled four times in visible light photocatalytic water splitting experiments without any loss in activity.

H2 Production Under Visible Light Irradiation from Aqueous Methanol Solution on CaTiO3:Cu Prepared by Spray Pyrolysis

Perovskite-type photocatalysts of CaCuxTi1−xO3 (0 ≤ x ≤ 0.02) powder were prepared by spray pyrolysis of aqueous solution or aqueous solution with polymeric additive. The effects of the amount of copper ions doped in the photocatalyst and the precursor type on the photocatalytic activity under visible-light irradiation were investigated. The crystal structure, oxidation state, and light adsorption properties of the prepared photocatalysts were analyzed using x-ray diffraction, x-ray photoelectron spectroscopy, and diffuse reflectance spectroscopy, respectively. The doping of copper ions in CaTiO3 allowed visible-light absorption owing to a narrowing of the band gap energy of the host material through the formation of a new donor level for copper ions. Among the doped samples prepared from the aqueous precursor, CaTiO3 doped with 1 mol.% copper ions had the highest hydrogen evolution rate (140.7 μmol g−1 h−1). Notably, the hydrogen evolution rate of the photocatalyst doped with 1 mol.% copper ions prepared from the aqueous precursor with polymeric additive (295.0 μmol g−1 h−1) was two times greater than that prepared from the aqueous precursor, due to the morphology effect.

Perylene‐Containing Conjugated Microporous Polymers for Photocatalytic Hydrogen Evolution

Three perylene‐containing conjugated microporous polymers (PrCMPs) are synthesized via Suzuki–Miyaura cross‐coupling reaction from perylene with four polymerizable functional groups and a range of different substituted benzene derivatives. The pore property and bandgap of the resulting PrCMPs can be tuned by changing the comonomer of benzene with different substituted groups and positions. The photocatalytic performances of the polymers are highly dependent on the surface area, geometry, and bandgap of the PrCMPs. It was found that the 1,2,4,5‐linked polymer of PrCMP‐3 shows the highest hydrogen evolution rate (HER) of 12.1 µmol h−1 under UV–vis light irradiation among the three polymers because of its high surface area, broad light absorption, and suitable bandgap. PrCMP‐3 also exhibits good photocatalytic stability for prolonged hydrogen production reaction. This result demonstrates that the crucial role of the linkage geometry offers a general principle for the rational design of conjugated microporous polymer photocatalysts. image

Counteracting Blueshift Optical Absorption and Maximizing Photon Harvest in Carbon Nitride Nanosheet Photocatalyst.

Blueshift of optical absorption and corresponding widening of the bandgap is a fundamental problem with 2D carbon nitride nanosheets (CNNS). An additional problem is low quantum yields (<9%) due to higher loss of absorbed photons. These problems impose a significant restriction to photocatalytic performance of CNNS. Therefore, the synthesis of narrow bandgap CNNS with high quantum efficiency is of pressing research importance. This contribution reports melem-derived narrow bandgap CNNS with a record-low bandgap of 2.45 eV. The narrowing in bandgap comes with improved optical absorption and use of visible-light photons together with excellent charge transport dynamics. This is demonstrated by a record high hydrogen evolution rate of 863 µmol h-1 with apparent quantum efficiency of 16% at 420 nm.

Structure-property relationships for covalent triazine-based frameworks: The effect of spacer length on photocatalytic hydrogen evolution from water

Covalent triazine-based frameworks (CTFs) are a subclass of conjugated microporous polymers (CMPs) that can be used as organic photocatalysts for photocatalytic hydrogen evolution from water. Seven materials with varied spacer units from phenylene to quarterphenylene were synthesized, either by trifluoromethanesulfonic acid (TfOH) catalysis from nitriles or by Suzuki-Miyaura polycondensation. The photocatalytic performance under visible light of all materials was systematically studied in the presence of a hole-scavenger, showing that both synthesis routes produce CTFs with similar hydrogen evolution rates (HER), but different optical properties. The highest hydrogen evolution rate in the cyclotrimerized series was found for CTF-2 with an apparent quantum yield of 1.6% at 420 nm in a mixture of water and triethanolamine with a platinum co-catalyst. Based on (TD-)DFT calculations, the highest performance was expected for CTF-1 and this discrepancy is explained by a trade-off between increased light absorption and decreased thermodynamic driving force.

One-pot hydrothermal synthesis of CdS/NiS photocatalysts for high H2 evolution from water under visible light

The development of efficient and stable noble-metal-free photocatalysts is crucial for hydrogen evolution from water splitting as clean energy. This study reports uniform CdS/NiS spherical nanoparticles through a simple one-pot hydrothermal method with the aid of KOH. The prepared CdS/NiS composites show superior photocatalytic activities toward the water splitting under visible light. A suitable amount of KOH in the synthesis benefits to form CdS/NiS photocatalysts with the improved activity. The CdS/NiS composite including 10 mol% metal percentage of Ni exhibits the highest photocatalytic activity. The high hydrogen evolution rate of 24.37 mmol h−1 g−1 is achieved over the CdS/NiS composite photocatalyst. The CdS/NiS photocatalyst has good photocatalytic stability in the recycling uses. The present CdS/NiS as a noble-metal-free photocatalyst provides the superior visible-light driven catalytic activity for hydrogen evolution.