Efficient Photocatalytic Hydrogen Production Research Articles

Design and Fabrication of ternary Au/Co3O4/ZnCdS spherical composite photocatalyst for facilitating efficient photocatalytic hydrogen production

Design and Fabrication of ternary Au/Co3O4/ZnCdS spherical composite photocatalyst for facilitating efficient photocatalytic hydrogen production

Constructing core–shell phosphorus doped MnCo2O4.5@ZIS for efficient photocatalytic hydrogen production from water splitting

Rational construction of core@shell heterostructured photocatalysts is the key to realize efficient hydrogen production from water splitting attributing to the accelerated photoinduced charges separation/transfer and enhanced light absorption ability. In this work, two-dimensional (2D) ZnIn2S4 (ZIS) nanosheets were in-situ grown on phosphorus doped MnCo2O4.5 (P-MnCo2O4.5) nanospheres to construct P-MnCo2O4.5@ZIS heterostructured photocatalysts for efficient photocatalytic hydrogen production. The optimized 6 wt% P-MnCo2O4.5@ZIS composite presents remarkable photocatalytic hydrogen evolution rate of 4197 µmol g−1 h−1 (8 times of single ZIS) along with excellent cycling stability, which is comparable to most previous reported ZnIn2S4-based or even noble-metal involved catalysts. The improved photocatalytic performance is resulted from the distinguished heterostructure and components of P-MnCo2O4.5@ZIS, in which the close contact interface facilitates the separation/transfer and inhibits the recombination of charges, and the uniform distribution of ZIS nanosheets on P-MnCo2O4.5 increases the active sites and fortifies the light absorption. The present work comes up with a prospective method for establishing core@shell ZIS-based heterostructured photocatalysts for efficient hydrogen generation.

Engineered self-assembled protein nanosheets for in situ biosynthesis of peptide anchored protein-semiconductor hybrids for efficient hydrogen production

Catalytic hydrogen production using solar energy is of great significance in addressing the global energy crisis. Herein, an efficient artificial photocatalytic hydrogen production system based on hierarchical protein self-assembly is designed and developed by in situ biosynthesis of peptide-anchored protein-semiconductor hybrids. The self-grown protein-CdS quantum dot hybrids stabilize and array orderly by the predesigned bioengineered proteins assembled into monolayer nanosheets, perfectly mimicking both the structure and function of the natural photosynthetic system. By mild deposition of Pt nanoparticles, the photocatalytic hydrogen production performance of the system is further enhanced to 69100 μmolh−1 (Cd2+) g −1, 80 times the catalytic activity of free CdS. Remarkably, the protein 2D network effectively enhances the water solubility, dispersibility, and solution stability of the inorganic catalytic centers, affording efficient photocatalytic hydrogen evolution. The system maintains 91.2 % catalytic efficiency after 30 days. Furthermore, its hydrogen production rate can be artificially regulated between 69100 and 52100 μmolh−1 (per g Cd2+) by the assembly-disassembly process of the protein templates. Thus, our work showcases the importance of the protein template and its assembly in maintaining the structural stability and high catalytic performance of the photocatalytic system and provides promising ideas for the simulation of natural photosynthetic systems.

Enhancing Photocatalytic Hydrogen Production Efficiency with Carbon Fibers: A Mini Review

Enhancing Photocatalytic Hydrogen Production Efficiency with Carbon Fibers: A Mini Review

Efficient photocatalytic hydrogen production via single-atom Pt anchored hydrogen-bonded organic frameworks

Constructing single-atom catalysts (SACs) using organic porous framework materials as supports presents a promising approach for developing highly efficient photocatalysts for hydrogen evolution. However, the fabrication of SACs that are both highly stable and active poses a significant challenge, particularly in the precise anchoring of metal single atoms. In this study, we utilized 1,3,6,8-tetra (p-methyl benzoate) pyrene as a ligand to synthesize pyrene-based hydrogen-bonded organic frameworks (denoted as PFC-1) through a self-assembly approach. Subsequently, a liquid-phase photoreduction process was employed to deposit noble metal platinum (Pt) onto PFC-1, resulting in the fabrication of SACs (PFC-1@Pt). Characterization results confirmed that Pt existed in a monatomic state, anchored through PtC and PtO coordination bonds with PFC-1. Serving as electron capture and separation centers, the Pt single atoms effectively suppressed electron-hole recombination, thereby prolonging carrier lifetimes. Consequently, the PFC-1@Pt SAC exhibited efficient hydrogen evolution performance with a rate of 2202.5 μmol g−1 h−1 and maintained photocatalytic activity for over 40 h. Our findings provide a systematic approach for developing efficient and stable SACs based on HOFs, expanding the potential applications of HOF materials in photocatalysis.

Photocatalytic Ammonia Decomposition Using Dye-Encapsulated Single-Walled Carbon Nanotubes

The photocatalytic decomposition of ammonia to produce N2 and H2 was achieved using single-walled carbon nanotube (SWCNT) nanohybrids. The physical modification of ferrocene-dye-encapsulated CNTs by amphiphilic C60-dendron yielded nanohybrids with a dye/CNT/C60 coaxial heterojunction. Upon irradiation with visible light, an aqueous solution of NH3 and dye@CNT/C60-dendron nanohybrids produced both N2 and H2 in a stoichiometric ratio of 1/3. The action spectra of this reaction clearly demonstrated that the encapsulated dye acted as the photosensitizer, exhibiting an apparent quantum yield (AQY) of 0.22% at 510 nm (the λmax of the dye). This study reports the first example of dye-sensitized ammonia decomposition and provides a new avenue for developing efficient and sustainable photocatalytic hydrogen production systems.

Comparative Study on Photocatalytic Hydrogen Production Efficiency of Benzodifuran-Based Covalent Organic Frameworks: Impact of Carboxamide and Ethyl Carboxylate Side Chains

Comparative Study on Photocatalytic Hydrogen Production Efficiency of Benzodifuran-Based Covalent Organic Frameworks: Impact of Carboxamide and Ethyl Carboxylate Side Chains

Trinuclear iron-oxo cocatalyst regulating new electron transfer pathway in Pt loaded bismuth oxychloride for efficient photocatalytic hydrogen production

BiOCl, a traditional p-type semiconductor, finds extensive application in photocatalytic oxidation and degradation, whereas it is less common in photocatalytic water splitting and hydrogen production. Here, the photocatalytic hydrogen production performance of black BiOCl has been examined by the introduction of noble metal platinum and cocatalyst trinuclear iron-oxo cluster. During the 5-h photocatalytic process, the established system significantly augments the hydrogen production efficiency of black BiOCl by an estimated factor of 8.53. Under illumination, trinuclear iron-oxo clusters provide electron recombination with holes in the valence band of the catalyst, thereby increasing the utilization of photogenerated electrons. Additionally, since the specific energy level structure has a significant impact on the cocatalyst function, trinuclear iron-oxo clusters can be suitable in a variety of photocatalytic systems. This new endeavor might present creative design approaches and low-cost cocatalyst alternatives for the photocatalytic hydrogen evolution from the water splitting of conventional p-type semiconductor materials.

Rational construction of ZnIn2S4/Co3Se4 with boosted photocatalytic hydrogen production through cooperate with S-scheme heterojunction and photothermal effect

The rational design of excellent visible light photocatalysts that efficiently utilize the solar spectrum is urgently needed. In this work, ZnIn2S4 (ZIS) and Co3Se4 (CS) were coupled by a multistep process involving simple ultrasonic self-assembly and calcination to form ZnIn2S4/Co3Se4 (ZIS/CS) photocatalysts with synergistic S-scheme heterojunctions and photothermal effects, which realized efficient photocatalytic hydrogen (H2) production with optimal H2 yield of 2.46 mmol h−1 g−1, superior to pure ZIS (0.47 mmol h−1 g−1) by a factor of 5.23. The excellent cyclic stability and wide environmental adaptability to the ionic environment of water of ZIS/CS were proved. The positive impaction of photothermal effect on the H2 yield of ZIS/CS was investigated and confirmed by the temperature change of photocatalysts powder or photocatalytic system under light irradiation. In addition, based on a series of characterization analyses and first-principle simulation calculations, a charge transfer pathway for ZIS/CS S-scheme heterojunctions was proposed. This work provides valuable ideas and feasible research methods for the design of stable and practical photocatalysts.

Chiral Pd(II) Nanofiber Promoting Electron Transfer of g-C3N4 for Efficient Photocatalytic Hydrogen Production.

The rapid transfer and separation of photogenerated electrons is very important for the improvement of photocatalytic efficiency. Here, chiral induced spin selectivity effect (CISS effect) was developed to accelerate electron transfer for efficient photocatalytic hydrogen production. A chiral and achiral racemic supramolecular Pd(II) complex nanofiber was fabricated via supramolecular self-assembly of chiral L-Py or its racemes with Pd(II) and used to modify carbon nitride (g-C3N4). The obtained chiral photocatalyst L-Py-Pd/g-C3N4-4 and achiral photocatalyst Rac-Pd/g-C3N4-4, show enhanced photocatalytic activities with hydrogen evolution rates of 2476 and 1339 μmol g-1 h-1, respectively, while that of pure g-C3N4 is 30.5 μmol g-1 h-1. Chiral photocatalyst has 85% higher activity than achiral one and is 82.5-fold of pure g-C3N4, due to better suppression of the recombination of photogenerated electron-hole pairs in the interface of g-C3N4 contact with chiral molecule. Spectral tests and photoelectrochemical tests proved that the chiral supramolecular Pd(II) complex can act both as an electron spin filter and hydrogen reduction catalytic center to enhance photocatalytic efficiency. This work offers a new route to facilitate electron transfer by the CISS effect for photocatalytic hydrogen evolution.

Fabrication of In-doped CdSe/Zn3In2S6 type II heterojunction composite for efficient photocatalytic hydrogen evolution

Conversion of water into renewable hydrogen energy using solar energy is one of the ideal methods to address the current environmental pollution and increasing energy demand. Thus developing the photocatalyst with high efficiency, stability, and a low electron-hole recombination rate becomes very important. In this paper, Zn3In2S6 microspheres were synthesized by hydrothermal method, and then In-doped CdSe nanoparticles were loaded on the surface of Zn3In2S6 microspheres to form Cd0.9In0.1Se/Zn3In2S6 type II heterojunction. Under simulated sunlight irradiation, the photocatalytic hydrogen production of Cd0.9In0.1Se/Zn3In2S6 reached 11.41 mmol h−1 g−1, which was 4.61 times and 1.97 times that of Cd0.9In0.1Se and Zn3In2S6, respectively. The experimental results showed that the formation of type II heterojunction could improve the photocatalytic hydrogen production efficiency by shortening the charge transport distance and inhibiting the recombination of electron-hole pairs. This work will provide new ideas and insights for the development of photocatalytic hydrogen production technology.

Vinyl-functionalized covalent organic framework via tuning π-conjugation effectively promotes photocatalytic hydrogen evolution

Covalent organic frameworks (COFs) show great potential in photocatalytic water splitting. However, it is still crucial to explore the effect of π-conjugation of COFs on photocatalytic performance. Here, a series of COFs with different degrees of conjugation (DHTA-BD COF, DHTA-STP COF, DHTA-AZO COF) have been investigated through the synergistic effect of varying the planarity and π electronic structures. The results show that the vinyl-functionalized DHTA-STP COF achieves an excellent photocatalytic hydrogen generation rate of 16.1 mmol g1h−1 under visible light conditions, 4.3 times higher than the DHTA-BD COF, and the hydrogen production of the DHTA-AZO COF is extremely low under the same test conditions. Moreover, the synergistic effect of the smaller dihedral angle and ordered π electronic structures with the introduction of vinyl structure in DHTA-STP COF leads to a higher degree of conjugation, facilitating π delocalization efficiency and promoting the redistribution of charges. Experimental and theoretical calculations have demonstrated that DHTA-STP COF is a promising photoactive semiconductor with the strongest photocurrent, the smallest impedance, the narrowest electronic bandgap, and the strongest separation ability of electron-hole pairs. This finding provides guidance for introducing appropriate conjugated units into COFs to improve the photocatalytic hydrogen production efficiency.

Enhanced hydrogen evolution performance of twinned Mn0.65Cd0.35S with Zn-doped cadmium selenide under visible light irradiation

The cadmium manganese sulfide, despite being recognized as a highly efficient photocatalytic semiconductor for hydrogen evolution, faces significant challenges in terms of charge recombination when used solely as a catalyst for photocatalytic hydrogen production. The construction of heterojunction photocatalysts is regarded as one of the effective strategies to enhance the efficiency of photocatalytic hydrogen production. In this work, Zn-doped CdSe was adopted to enhance the photocatalytic active sites of the twinned Mn0.65Cd0.35S. As results, the photocatalytic hydrogen evolution of Zn–CdSe-1/T-MCS-40 can reach approximately 47447.15 μmol g−1 after 5 h, representing a 15 times increase compared to Mn0.65Cd0.35S. Besides, the hydrogen evolution rate shows almost no significant attenuation after four consecutive cycles (20 h). The significant achievement can be largely attributed to the successful construction of an S-scheme heterojunction of Zn–CdSe-1/T-MCS-40, which effectively minimized the charge transfer distance and suppressed the recombination of photo-generated electron-hole pairs. Additionally, the incorporation of Zn-doped CdSe significantly expands the response range to visible light, thereby providing a conceptual framework for advancing the design of solar-to-chemical energy conversion and effectively guiding the fabrication of metal sulfide-based photocatalytic heterojunctions.

In situ Construction of Single‐Atom Electronic Bridge on COF to Enhance Photocatalytic H2 Production

AbstractPhotocatalytic hydrogen production is one of the most valuable technologies in the future energy system. Here, we designed a metal‐covalent organic frameworks (MCOFs) with both small‐sized metal clusters and nitrogen‐rich ligands, named COF‐Cu3TG. Based on our design, small‐sized metal clusters were selected to increase the density of active sites and shorten the distance of electron transport to active sites. While another building block containing nitrogen‐rich organic ligands acted as a node that could in situ anchor metal atoms during photocatalysis and form interlayer single‐atom electron bridges (SAEB) to accelerate electron transport. Together, they promoted photocatalytic performance. This represented the further utilization of Ru atoms and was an additional application of the photosensitizer. N2‐Ru‐N2 electron bridge (Ru‐SAEB) was created in situ between the layers, resulting in a considerable enhancement in the hydrogen production rate of the photocatalyst to 10.47 mmol g−1 h−1. Through theoretical calculation and EXAFS, the existence position and action mechanism of Ru‐SAEB were reasonably inferred, further confirming the rationality of the Ru‐SAEB configuration. A sufficiently proximity between the small‐sized Cu3 cluster and the Ru‐SAEB was found to expedite electron transfer. This work demonstrated the synergistic impact of small molecular clusters with Ru‐SAEB for efficient photocatalytic hydrogen production.

Scalable fabrication of high surface area g-C3N4 nanotubes for efficient photocatalytic hydrogen production

In this research, we present a novel facile, scalable, and template-free technique of synthesizing graphitic carbon nitride (g-C3N4) nanotubes for generating hydrogen through photocatalysis. The hybrid technique involves a two-fold mixing of the precursor materials melamine (M) and cyanuric acid (CA), involving ball milling followed by solution mixing. By varying the M:CA molar ratios, different compositions of g-C3N4 nanotubes were fabricated. The study focused on examining the surface characteristics and the photocatalytic hydrogen evolution performance of these nanotubes. Nanotubes with high specific surface area of 206 m2 g−1 for M:CA molar ratio of 1:3 and 178 m2 g−1 for M:CA molar ratio of 1:5 were produced, with H2 evolution rates of 543 μmol h−1 g−1 and 740 μmol h−1 g−1 respectively, which were an increase of 4 and 5-fold, respectively, in comparison to the pristine sample. The enhanced efficiency of hydrogen production through photocatalysis by nanotubes, when contrasted with pristine material, can be ascribed to their high crystallinity, superior specific surface areas, decreased recombination rates of electron-hole pairs generated during light exposure, and improved dynamics of charge carriers. This hybrid technique provides a new pathway for cost-effective fabrication of g-C3N4 nanotubes with substantial surface areas and high yield photocatalysts on an industrial scale, without the use of templates and hydrothermal processes for efficient hydrogen generation.

A special coupling strategy: Cu2MoS4 as a large-sized co-catalyst for promoting photocatalytic hydrogen production performance

The photocatalytic hydrogen production performance of semiconductor materials can be improved by co-catalyst modification. In most of the studies, the size of the co-catalyst is relatively small compared to the primary catalyst. However, in this study, we employed a novel strategy by synthesizing a relatively large-sized Cu2MoS4 as the co-catalyst and in situ loading smaller-sized Zn0.5Cd0.5S onto Cu2MoS4, verifying that Cu2MoS4 enhances the photocatalytic hydrogen production efficiency of Zn0.5Cd0.5S. It can be observed by scanning electron microscopy (SEM) that the lateral size of 2D Cu2MoS4 is at least 50 times larger than the Zn0.5Cd0.5S nanoparticle particle size. In addition, Density Functional Theory (DFT) calculations have demonstrated that the active site for hydrogen production in the composite is located in Cu2MoS4. The large-sized of Cu2MoS4 not only provides more active sites but also broadens the electron transport channel, which is conducive to promoting the transfer of photogenerated electrons from Zn0.5Cd0.5S. This work enriches the study of large-sized materials as co-catalyst and provides a strategy for the construction of composite catalysts.

Modulation of π-Electron Density in Ultrathin 2D Layers of Graphite Carbon Nitride for Efficient Photocatalytic Hydrogen Production.

The rational design and synthesis of novel semiconductor nano-/quantum materials have been ambitiously pursued in the field of photocatalysis as the technology is promising and critical for attaining future energy and environmental sustainability. Herein, the integrity of aromatic carbon into graphitic carbon nitride (CN) at the same molecular plane with a few 2D layers is achieved by using modulated precursors of CN, forming carbon regulated ultrathin CN (CUCN) with improved charge transfer kinetics and photocatalytic hydrogen production. The grafted graphite rings adjacent to carbon nitride frameworks induce a significant rearrangement and relocalization of the overall framework, and form conjugated sp2 hybridized interfaces and internal electric fields that drive the separation and directional transfer of photogenerated electrons from CN sheets towards intralayer graphite regions, where the photocatalytic hydrogen evolution reaction occurs extensively, yielding largely increased HER rate of 2231.8 µmol g-1 h-1 by 8.2 times relative to CN, as well as a remarkable apparent quantum yield of 2.93% under monochromatic light at 420 nm. The high physicochemical stability and low synthesis cost of CUCN make it a potential benchmark photocatalyst that can be readily modified via element doping, heterojunction introduction, defect engineering, and so on, to further enhance its HER performance.

Development of Modified TiO2 for Photocatalytic Hydrogen Production

AbstractTiO2 has advantages such as excellent photocatalytic performance, high chemical stability, low price, and not easy to produce secondary pollution. Therefore, the photocatalytic hydrogen production over TiO2 catalyst was an effective way to achieve hydrogen production from solar energy with low energy consumption and low cost. However, the TiO2 catalyst responds only to UV light due to its wide forbidden band, and the electrons and holes were prone to recombination, resulting in the decrease in photocatalytic activity and quantum efficiency. In recent years, researchers have conducted a series of modifications on TiO2 to improve its visible light response, reduce the rate of carrier recombination, and thereby enhance the efficiency of photocatalytic hydrogen production. This paper reviews several main modification methods of TiO2 including morphology regulation, ion doping, semiconductor recombination, noble metal deposition, dye sensitization and their research progress in the field of photocatalytic hydrogen production. Finally, the modification of TiO2 photocatalyst in the future was predicted.

Up-conversion luminescence and Bi SPR effect promoted Z-scheme BiVO4(040)-Bi-(NaYF4:Er,Yb,Tm@BiOBr)/Bi photocatalyst for efficient photocatalytic hydrogen production with simultaneous degradation of malachite green

Photocatalytic hydrogen production with simultaneous degradation of organic pollutants by using solar energy provide a promising strategy to solve the energy and environmental issue in the future. However, for onefold wide band-gap semiconductor, the poor photocatalytic efficiency limits its application on a large scale due to its easy recombination of photo-generated electron-hole pairs and low solar energy utilization. Herein, a novel Z-scheme BiVO4(040)-Bi-(NaYF4:Er,Yb,Tm@BiOBr)/Bi photocatalyst is prepared via photo-assisted isoelectric point method. In this composite photocatalyst, up-convention luminescence material, NaYF4:Er,Yb,Tm, can offer more ultraviolet light and visible light to intensify the activations of BiOBr and metal Bi nanoparticles, respectively. Furthermore, the formation of Z-scheme BiVO4(040)-BiOBr photocatalystic sytem, the spatial separation of the BiVO4(040) and BiVO4(110) facets and the presence of metal Bi surface plasmon resonance effect are contributed to the high-efficiency separation of the photo-generated electron-hole pairs. The experimental results show that as-prepared Z-scheme BiVO4(040)-Bi-(NaYF4:Er,Yb,Tm@BiOBr)/Bi photocatalyst exhibits advanced photocatalytic hydrogen production amount (192.0 μm) and excellent degradation ratio of malachite green (88.51 %) under simulated sunlight irradiation for 5.0 h. The apparent quantum yield of the Z-scheme BiVO4(040)-Bi-(NaYF4:Er,Yb,Tm@BiOBr)/Bi photocatalyst at 420 nm reaches a specific value of 5.8 %. In addition, Z-scheme BiVO4(040)-Bi-(NaYF4:Er,Yb,Tm@BiOBr)/Bi photocatalyst also remains a high stability in the photocatalytic hydrogen production with simultaneous degradation of malachite green within six reuse. At last, the possible reaction mechanism and degradation pathways of malachite green caused by Z-scheme BiVO4(040)-Bi-(NaYF4:Er,Yb,Tm@BiOBr)/Bi photocatalyst under simulated sunlight irradiation are put forward.

Construction of 2D/2D S-scheme Bi2MoO6/Zn-TCPP heterojunction via in-situ self-assembly growth strategy to enhance interface effect for efficient photocatalytic hydrogen production

Two-dimensional/two-dimensional (2D/2D) heterojunctions are considered to be an effective strategy for forming strong interface effects and facilitating photogenerated carrier separation. However, it is usually limited by the size mismatch of the materials, even at the expense of its redox capability. Herein, 2D/2D S-scheme heterojunction photocatalyst Bi2MoO6/Zn-TCPP (BMO/ZTP) composed of 2D Bi2MoO6 and 2D Zn-TCPP (TCPP: tetrakis (4-carboxyphenyl) porphyrin) (MOFs) was constructed by in-situ self-assembly growth strategy. The size-compatible 2D/2D composites had abundant surface active sites and strong interactions. In addition, band bending and interfacial electric field (IEF) effect based on S-scheme heterojunction could accelerate the separation and migration of photogenerated carriers in BMO/ZTP. The best hydrogen precipitation rate of the BMO/ZTP was 10900.94 umol·g−1·h−1, which was 38.90 and 3.24 times higher than that of Bi2MoO6 (280.26 umol·g−1·h−1) and Zn-TCPP (3360.34 umol·g−1·h−1), respectively. The results indicated that 2D/2D BMO/ZTP S-scheme heterojunction could enhance the interface effect and retain strong reducing electrons to achieve efficient photocatalytic hydrogen production, which was confirmed by ultraviolet photoelectron spectroscopy (UPS), Tafel curve, electron spin resonance (ESR) and time-resolved photoluminescence (TRPL) characterization and density functional theory (DFT) calculations. This work provided a general strategy for constructing 2D Bi2MoO6 and 2D MOFs S-scheme heterojunctions to enhance interface effects for achieving efficient photocatalytic hydrogen production.