Efficient Photocatalytic Hydrogen Evolution Research Articles

Electron-rich pyrimidine rings enabling crystalline carbon nitride for high-efficiency photocatalytic hydrogen evolution coupled with benzyl alcohol selective oxidation

With electron-rich pyrimidine rings introduced, the obtained crystalline PCN is favored with rationally modulated band and electronic structures, resulting in efficient photocatalytic hydrogen evolution and benzyl alcohol selective oxidation.

Efficient photocatalytic hydrogen evolution and CO2 reduction by HfSe2/GaAs3 and ZrSe2/GaAs3 heterostructures with direct Z-schemes.

The elaborate configuration of the heterostructure is crucial and challenging to achieve high solar-to-hydrogen efficiency or CO2 reduction efficiency . Here, we predict two heterostructures composed of HfSe2, ZrSe2, and GaAs3 monolayers. The maximum of 42.71%/35.12% with the heterostructures can be reached with the perfect match between the bandgap and band edges. The configurations of the heterostructures are discovered from 12 possible stacking types of the three monolayers. The formation energy, potentials of band edges, carrier mobilities, and optical absorption were used to identify the feasibility of the CO2 reduction reaction (CO2RR), the hydrogen evolution reaction (HER), and the oxygen evolution reaction (OER). The and based on overpotentials and bandgaps and the Gibbs free energies (ΔGs) are evaluated to quantificationally access the photocatalytic performance of the constructed heterostructures. The results demonstrate that high can be obtained for the solar photocatalytic Z-schemes with the HfSe2/GaAs3 and ZrSe2/GaAs3 heterostructures, and these values can be further enhanced through strain engineering. Moreover, small changes in ΔGs were observed for HER, OER, and CO2RR. Therefore, the two heterostructures have excellent performance in photocatalytic hydrogen evolution and CO2 reduction. The results of the electronic properties revealed that the delicate matching of the projected band edges of the monolayers in the heterostructures is responsible for the high photocatalytic performance.

Hydroxylated organic semiconductors for efficient photovoltaics and photocatalytic hydrogen evolution

Two –OH-based organic semiconductors with long-wavelength absorption and a high LUMO were developed as acceptors in bulk heterojunctions for organic solar cells (a PCE of 16.71%) and photocatalytic hydrogen evolution (an EQE of 9.17% at 800 nm).

Ultrathin black TiO2 nanosheet-assembled microspheres with high stability for efficient solar-driven photocatalytic hydrogen evolution

We applied a small amine molecule protective agent to synthesize high-thermally stable black TiO2 with high specific surface area, broad optical absorption, and increased charge separation, which exhibits excellent photocatalytic performance.

C4N quantum dots/g-C3N4 nanosheets organic homogeneous structure self-assembly for efficient charge separation and photocatalytic hydrogen evolution

C4N quantum dots/g-C3N4 nanosheets composites are prepared via self-assembly process, which show excellent photocatalytic H2 production, 2 times than original g-C3N4 nanosheets due to narrow band gap and unique band structure of C4N quantum dots.

Highly-efficient photocatalytic hydrogen evolution triggered by spatial confinement effects over co-crystal templated boron-doped carbon nitride hollow nanotubes

Hollow nanotube-like boron-doped carbon nitride for efficient photocatalytic hydrogen evolution.

Enwrapping graphdiyne (g-CnH2n−2) on hollow NiCo2O4 nanocages derived from a Prussian blue analogue as a p–n heterojunction for highly efficient photocatalytic hydrogen evolution

A new carbon material of graphdiyne (g-CnH2n−2) was prepared by reduction elimination reaction assisted by ball milling and the coupling of NiCo2O4 and GDY to construct a p–n heterojunction for highly efficient photocatalytic hydrogen evolution.

S-doped C3N5 derived from thiadiazole for efficient photocatalytic hydrogen evolution

Novel structured thiadiazole-attached carbon nitrides are first synthesized via sintering 5-amino-1,3,4-thiadiazole-2-thiol, demonstrating excellent performances towards photocatalytic H2 evolution under visible light irradiation.

Boosting photocatalytic H2 evolution through interfacial manipulation on a lotus seedpod shaped Cu2O/g-C3N4 p-n heterojunction

A novel lotus seedpod shaped Cu2O/g-C3N4 p–n heterojunction composite was fabricated by in situ filling the g-C3N4 framework with Cu2O hollow nanospheres for efficient photocatalytic hydrogen evolution.

MnS/Mn0.5Cd0.5S nanorods modified with Cu2MoS4 nanoplates for efficient photocatalytic hydrogen evolution

In this paper, a series of highly efficient, noble metal-free 2D lamellar Cu2MoS4 modified 1D short rod-like MnS/Mn0.5Cd0.5S nanocomposites were obtained by hydrothermal impregnation.

Anchoring 0D Cd0.5Zn0.5S nanoparticles on a 3D porous N-doped Ti3C2Tx MXene matrix for efficient photocatalytic hydrogen evolution

The accessibility of photogenerated charge transfer channels and the activity of catalytic reaction sites are critical for efficient hydrogen evolution reaction (HER).

Synthesis of hierarchical Cd-Ni-MOF micro/nanostructures and derived Cd-Ni-MOF/CdS/NiS hybrid photocatalysts for efficient photocatalytic hydrogen evolution.

Hierarchical micro/nanostructures assembled from nanorods and nanosheets have become promising candidates for photocatalysis. In this work, a series of hierarchical Cd-Ni-MOF micro/nanostructures, assembled from nanosheets and nanorods, were fabricated via a two-step solvothermal process involving the partial replacement of Ni2+ with Cd2+ in the Ni-MOF-74 structure. Different morphologies were obtained by considering different volume ratios of DMF and ethanol as the solvent during synthesis. Hierarchical Cd-Ni-MOF-T/CdS/NiS hybrid micro/nanostructures were synthesized by Ni2+ and Cd2+ exchange of Cd-Ni-MOFs with S2-. The as-prepared samples, which were composed of thin nanosheets alone, exhibited the best photocatalytic H2 evolution rate of about 40.08 mmol g-1 h-1. The p-n junction between CdS and NiS was found to be beneficial for the migration of photogenerated electrons from the conduction band (CB) of NiS to the CB of CdS. The heterojunction between CdS and Cd-Ni-MOF-T further promoted the transfer of an electron from the CB of CdS to the CB of Cd-Ni-MOF-T. Thus, this study demonstrated that hierarchical Cd-Ni-MOF-T/CdS/NiS architectures have a large specific surface area, leading to significantly improved photocatalytic activity.

2D photosensitive porphyrin-based MOFs integrated with a Pd cocatalyst with fast charge transfer for efficient photocatalytic hydrogen evolution

A series of 2D MOF nanosheets are prepared by a simple hydrothermal method for photocatalytic hydrogen production, in which PdTCPP integrates a photosensitive porphyrin with cocatalysts so as to realize fast charge carrier transport.

Co-P bond effect on an MOF-derived Co9S8 hollow polyhedron supported Ni2P co-catalyst for efficient photocatalytic hydrogen evolution.

The development of new, efficient noble-metal-free photocatalysts is of great significance for the photocatalytic hydrogen evolution reaction. Herein, Co9S8 with a hollow polyhedral structure was synthesized by in situ sulfurization of ZIF-67, and subsequently, Co9S8@Ni2P composite photocatalytic materials were prepared by loading Ni2P on the surface of Co9S8 through a solvothermal method based on a morphology regulation strategy. The design of the 3D@0D spatial structure of Co9S8@Ni2P is favorable for the formation of photocatalytic hydrogen evolution active sites. Due to the excellent metal conductivity of Ni2P, Ni2P as a cocatalyst can accelerate the separation of photogenerated electrons from holes in Co9S8, thus providing a large number of available photogenerated electrons for photocatalytic reactions. It is worth mentioning that a Co-P chemical bond is formed between Co9S8 and Ni2P, which plays an active role in the transport of photogenerated electrons. The densities of states of Co9S8 and Ni2P were determined by density functional theory (DFT) calculations. The reduction of the hydrogen evolution overpotential and the formation of efficient charge-carrier transport channels on Co9S8@Ni2P were confirmed by a series of electrochemical and fluorescence tests. This study provides a new idea for the design of highly active noble-metal-free materials for the photocatalytic hydrogen evolution reaction.

Positioning hydrogen reaction sites by constructing CdS/CoNiMoS4 heterojunctions for efficient photocatalytic hydrogen evolution.

The high gravimetric energy density of hydrogen makes it an ideal chemical fuel to address the issues of fossil fuel depletion and environmental pollution. Even though transition metal sulfides (TMSs) have been extensively investigated as substitutes for noble metals, their effectiveness is still doubtful for practical applications. Herein, we introduce a facile and general strategy to fabricate heterojunctions with CdS nanorods and a multimetallic transition metal sulfide (CoNiMoS4) for enhanced photocatalytic activity. The CdS/CoNiMoS4 heterojunction will serve as a dual-function photocatalyst with enhanced visible light absorption capability offered by CdS and high charge transfer efficiency provided by CoNiMoS4 nanostructures. Moreover, CdS/CoNiMoS4 nanostructures exhibit the best photocatalytic performance to generate H2 with an amount of 31.9 mmol g-1 h-1, with a distinguished stability for over 25 h. This synthetic approach may offer a new strategy to create diverse heterojunctions with Earth-abundant multimetallic components, which may broaden their scope of application in catalysis.

Preparation and photocatalytic hydrogen evolution performance of square platform Cu2MoS4/lamellar ZnIn2S4

Square platform Cu2MoS4/lamellar ZnIn2S4 composites were prepared for enhancing the photocatalytic activity. The loading of lamellar ZnIn2S4 on the surface of Cu2MoS4 can improve the photocatalytic hydrogen evolution efficiency.

Sodium ion doped graphitic carbon nitride with high crystallinity for superior photocatalytic hydrogen evolution efficiency

Photogenerated electron decay kinetics studies unravel the correlation between high crystallinity of Na+-doped and NH4Cl-assisted Na+-doped graphitic carbon nitride and their superior photocatalytic water splitting hydrogen evolution activities.

Exposing high-activity (111) facet CoO octahedral loading MXene quantum dots for efficient and stable photocatalytic H2 evolution.

Photocatalytic splitting of water for hydrogen generation is a green and renewable solution for converting solar energy to chemical energy; thus, the development of high-performance and stable photocatalytic materials has emerged as a research hotspot recently. Herein, a heterostructure composite photocatalyst of octahedral CoO uniformly modified with novel nitrogen-doped MXene quantum dots (N-MQDs) is successfully designed using a typical solvothermal approach. The optimum photocatalytic hydrogen evolution efficiency of the prepared N-MQDs@CoO heterojunction composite is 82.54 μmol g-1 h-1 with visible light, which is 16.57 times higher compared to the pure CoO. A series of photoelectrochemical tests were further performed to elucidate the photocatalytic hydrogen evolution mechanism. The remarkable improvement of activity is primarily attributed to the synergistic interaction between the closely spaced interface contacts and energy level matching among high conductivity Ti3C2 MXene quantum dots with CoO octahedra, dramatically hastening the segregation and transfer of photo-generated carriers. This study provides new ideas for the construction of MXene quantum dot-based co-photocatalysts with highly efficient photocatalytic performance and stability toward solar energy conversion applications.

Ternary photocatalysts with electron modulation for efficient photocatalytic hydrogen evolution reactions: CdS-induced ring electrons transfer effect

To better utilize clean energy for the purpose of carbon neutrality, we designed and prepared the three-phase connected ternary tandem heterojunctions for the photocatalytic hydrogen evolution reaction. Notably, the variety bonding rings demonstrated by density functional theory raised the possibility of a special electrons transferred mechanism. Further, a unique ring electrons transfer mechanism extended the lifetime of the excitons and promoted their separation and transfer. In-situ XPS (X-ray photoelectron spectroscopy) and other characterizations were used to thoroughly characterize the ring electron transfer. The addition of the mid-component in three phase-connected heterojunctions changed the pathway of electrons transfer and increased photocatalytic hydrogen evolution reaction efficiency. As a consequence, this heterojunction exhibited an enhanced exciton lifetime, low exciton–hole recombination rate, and good photoelectric response, thus outperforming a traditional tandem heterojunction by 14.6%. This work provides novel insights into the directionally design, construction, and optimization of photocatalyst structures and exciton transfer mechanisms.

Fabrication of noble-metal-free hierarchical rectangular tubular S-scheme NiS/ZnIn2S4/AgIn(WO4)2 nanocomposite for highly efficient photocatalytic hydrogen evolution

Accelerating the separation and transfer of photoinduced charge carriers is crucial for designing photocatalysts with superior photocatalytic hydrogen evolution (PHE) activity. Herein, a novel rectangular tubular hierarchical NiS/ZnIn2S4/AgIn(WO4)2 heterostructure was established by in-situ growing ZnIn2S4 nanosheets on the surface of tubular AgIn(WO4)2 and NiS nanoparticles (NPs) further deposited as co-catalysts for the first time. Based on the experimental and theoretical calculation results, the fabrication of ZnIn2S4/AgIn(WO4)2 S-scheme heterojunction as well as NiS NPs as active centers could account for the fast photogenerated charge carriers transfer and enhanced PHE activity. Notably, under simulated sunlight irradiation, the optimal NiS/ZnIn2S4/AgIn(WO4)2 composite exhibited a high PHE rate of 4818 µmol·g−1·h−1 without adding any noble-metal co-catalyst, which was about 24 and 3.7 times higher than that of pure AgIn(WO4)2 and ZnIn2S4, respectively. Meanwhile, the rate was up to 83 % of the value of ZnIn2S4/AgIn(WO4)2 with 3 wt% platinum (Pt) as co-catalyst, which meant that NiS NPs could replace Pt as an efficient noble-metal-free co-catalyst. This work provided a feasible approach to utilize the synergistic effect between co-catalyst and heterojunction for constructing efficient photocatalytic systems, and further confirmed the potential application of AgIn(WO4)2 with the special tubular morphology for PHE reaction.