Hydrogen (H2) has been considered as a potential alternative energy candidate because it has high energy storage capacity and no hazardous by-products are produced upon its combustion; the production of H2 via the photocatalytic alcohol reforming has motivated a broad research interest. Here, we develop TiO2 photocatalyst coupled with photoacid generator (PAG) for significantly augmented photocatalytic H2 generation by catalytic reforming of neat methanol. The H2 evolution rate over TiO2-PAG is 1412.4 µmol g-1 h-1, which is 3.5 times higher than bare TiO2 (397.4 µmol g-1 h-1). The optimal sample exhibits an apparent quantum yield (AQY) of 5.68% at λ = 365 nm. The enhancement of the photocatalytic performance is due to abundant H+ ions generated from α-hydrogen abstraction by PAG, which can be effectively combined with photoinduced electrons from TiO2 and reduced to H2. In addition, strong metal-support interaction (SMSI) between Pt and TiO2 removes adsorbed H2 from the surface of Pt─TiO2, keeping the surface fresh and maintaining high efficiency and excellent recycling stability of obtained photocatalysts. The combination of the two emerging functional materials represents a simple but economical and powerful approach for highly efficient methanol photocatalytic reforming into hydrogen.

Graphitic carbon nitride (g-C3N4, known as CN) has attracted interest as an unassuming polymer semiconductor capable of harnessing visible light for hydrogen (H2) production. However, the fast recombination of photoinduced electrons and holes (e-/h+) remains a substantial problem. Here, we develop an innovative strategy involving the introduction of iodine pairs (I3-/I-) as a hole relay in the CN structure (CN-KI3-KI). In addition, a built-in electric field is introduced by integrating cationic methyl viologen ions (1,1 '-dimethyl-4,4 '-bipyridinium dichloride hydrate, MV2+) to establish an auxiliary electron-transfer channel over CN-KI3-KI, named CN-I3-/I--MV2+ nanocomposites, for the efficient generation of H2. The MV2+ molecules serve as a hot electron acceptor and function as an effective mediator for electron migration, finally transferring the photogenerated electrons from MV+(center dot) to platinum for H2 production from H+. The introduction of I3-/I- and MV2+ redox mediators leads to an efficient spatial separation of e-/h+ in the CN-I3-/I--MV2+ composite photocatalyst, significantly boosting photocatalytic hydrogen production. The H2 production rate of CN-I3-/I--MV2+ rises to 136.67 & micro;mol h-1 upon the addition of 1 wt% MV2+, surpassing 31.63 and 4.1 times the rate over CN (4.32 & micro;mol h-1) and CN-KI3-KI (33.33 & micro;mol h-1), respectively. A minimal decline in photocatalytic activity is observed after continuous illumination for up to 16 hours, indicating its excellent stability. The combination of two emergent functional molecules as an electron-hole relay provides a straightforward yet cost-effective and potentially effective method for excellent photocatalytic hydrogen generation under visible light irradiation. This study presents an innovative methodology for developing economically feasible materials that significantly improve solar-to-fuel conversion applications.

Precise interfacial engineering and rational component synergy are critical for high-performance photocatalysts but remain challenging to achieve. Here, we report a COF/nanocluster hybrid photocatalyst (NZT-1) constructed by a hydrogen-bonding-directed assembly strategy. The catalyst comprises a photoactive TP-TDS COF (a covalent organic framework built from 2,4,6-triformylphloroglucinol and 3,7-diaminodibenzo[b,d]thiophene-5,5-dioxide) and NiZnCo nanoclusters embedded in an N-doped carbon matrix (NiZnCo-NC). Unlike conventional physical mixing or random loading, this approach enables molecular-level interfacial wiring between the COF and the nanoclusters. Within the ternary cocatalyst, a synergistic division of roles is inferred: Ni acts as a structural stabilizer, Zn fine-tunes the Co d-band center to optimize hydrogen adsorption, and Co serves as the active site. This architecture achieves a photocatalytic H2 evolution rate of 439.8 mmol g-1 h-1 and an apparent quantum yield of 18.6% at 500 nm-competitive with the best noble-metal-free systems. This work demonstrates that molecular-level interfacial control combined with rational multi-metal synergy provides a new paradigm for efficient, earth-abundant artificial photosynthesis.

Visible light driven photocatalytic hydrogen evolution using sacrificial agents is a promising route for solar to chemical energy conversion. However, achieving efficient charge separation and migration in heterogeneous semiconductor photocatalysts through a one-photon excitation process remains challenging. In this work, we report a one-photon excitation approach by integrating polymeric carbon nitride (PCN) with gadolinium oxychloride (GdOCl) by a molten salt method for photocatalytic hydrogen evolution over PCN/GdOCl photocatalysts. Notably, the optimized PCN/GdOCl-1.5 exhibits an impressive H2 performance with a yield of 86.38 μmol h-1, surpassing bare PCN by a factor of 4.7. Additionally, PCN/GdOCl-1.5 showcases enhanced photocatalytic H2 production with an apparent quantum efficiency (AQE) of 6.17% under monochromatic light at 420 nm. The improved separation of photogenerated charge carriers and reduced recombination rates in PCN/GdOCl-1.5 were evidenced by photoluminescence (PL) and electrochemical impedance spectroscopy (EIS). In addition, the photocatalyst displays outstanding stability and retains its photocatalytic performance over five successive reaction cycles, thereby emphasizing the potential of PCN/GdOCl-1.5 for efficient and sustainable hydrogen evolution. The enhanced H2 evolution performance is attributed to visible light excitation of PCN, followed by GdOCl assisted interfacial charge regulation and built-in electric field (BIEF) driven charge carrier migration. This work provides insight into the design of PCN based heterojunction photocatalysts for sacrificial agent assisted photocatalytic hydrogen evolution.

The photocatalytic hydrogen (H2) evolution performance of graphitic carbon nitride (g-C3N4) named as CN is mainly limited by poor charge separation and low surface catalytic activity. To address these challenges, we report composite photocatalysts by integrating CN with cobalt embedded in nitrogen-doped carbon (CoNC) cocatalyst termed as CN/CoNC-X via a tailored pyrolysis strategy using urea and zeolitic imidazolate framework-67 (ZIF-67) precursors. In this work, CoNC serves as an efficient cocatalyst, where Co sites facilitate abundant surface-active sites for H2 production, while the NC framework enhances conductivity and promotes charge transport at the interfacial surface. The firm interface between CN and CoNC creates intrinsic electronic interactions that accelerate the flow of electrons from CN and hinder charge carrier recombination. The optimal CN/CoNC-5 composite achieves an optimized H2 production rate of 1794.1 mu mol h & horbar;1 g & horbar;1 under visible-light irradiation (lambda >= 420 nm), which is nearly 6.1-fold greater than bare CN (292.4 mu mol h & horbar;1 g & horbar;1). In addition, the optimal designed photocatalyst demonstrates stable H2 production over four consecutive reaction cycles under visible-light illumination for up to 16 h. This significant enhancement confirms the crucial role of the CoNC cocatalyst in tuning charge carrier dynamics and improving surface catalytic efficiency.

Photocatalytic water splitting, which converts solar energy into hydrogen fuel, is one of the most viable methods to address future energy demands. Herein, by introducing 1,4,7,10,13,16-hexaoxacyclooctadecane (crown ether) on the surface of graphitic carbon nitride (CN) via H-bonding and CH-π interactions, we prepare highly efficient potassium-18-crown-6 ether-modified carbon nitride (CN/K-5CE) nanocomposite photocatalysts by a simple modification method for augmented photocatalytic hydrogen production. The optimized CN/K-5CE hybrid photocatalyst displays an enhanced photocatalytic hydrogen production rate of 126.33 μmol h-1, which is 6.83-fold higher than that of CN (18.47 μmol h-1) and 3.76 times higher than that of CN/CE (33.58 μmol h-1). The optimal CN/K-5CE sample exhibits an AQE of 8.93% at λ = 420 nm. Furthermore, the stability test indicates no significant activity loss over the CN/K-5CE sample after 4 consecutive cycles. The experimental results and corresponding characterization unravel that the electride formation by the complexation of 18-crown-6 ether (CE) with an alkali metal potassium ion (K+) provides excess electrons in CN/K-5CE, resulting in a reduced band gap and increased electrical conductivity and hydrophilicity. Synergistic effect from the van der Waals (vdW) force interaction between CE and CN leads to efficient interfacial charge transportation and separation. Moreover, the presence of K+ cations facilitates water adsorption and dissociation on the catalyst, thus enhancing photocatalytic H2 evolution. Our study opens up an avenue to fabricate highly efficient and stable hydrophilic CN-based hybrid materials with tuned surface properties and electronic structures for practical solar-to-fuel conversion.

We report a visible light-induced hydrophosphinylation of unactivated alkenes catalyzed by a low-concentration photocatalyst (4CzIPN), affording a simple, efficient and environmentally friendly method for constructing C-P bonds. This method exhibits a broad substrate scope and synthetically useful yields, and its practicability is further demonstrated by gram-scale experiments. The mechanism was elucidated through detailed experimental studies and theoretical calculations. By comparing linear alkenes with functionalized alkenes, we gained insights into the radical process, which is beneficial for the development of synthetic strategies for tertiary phosphine oxides.

We highlighted the synthesis strategies, photocatalytic H2 production, and charge separation mechanisms of inorganic oxide semiconductor-based S-scheme heterojunctions, such as tungsten oxides, titanium oxides, zinc oxides, and copper oxides.

Graphitic carbon nitride (g-C3N4) termed CN has gained significant attention as a potential candidate for photocatalytic H-2 evolution owing to its visible-light absorption and adjustable electronic characteristics. However, its performance is confined by the fast charge carrier recombination and limited active sites. Recently, vacancy engineering has been identified as an efficient strategy to alter the electronic structure, optical absorption, and charge carrier separation of CN, thereby boosting its photocatalytic performance. Herein, we employ N-(4-cyanophenyl)-glycine (referred to as NCyPG) as a precursor to derive electron-deficient nitrogen vacancy (N-v) and urea as a CN precursor to construct NvCN-X (X = 1, 3, 5, and 7 mg of NCyPG) photocatalysts via a one-step pyrolysis. The experimental results show that N-v significantly expands optical absorption, enhances charge carrier separation and transport, and provides electron-trapping sites, thus augmenting H-2 evolution from water splitting. The best NvCN-3 photocatalyst culminates in a maximum H-2 evolution rate of 1632.0 mu mol h(-1) g(-1) upon visible light (lambda >= 420 nm) irradiation, which surpasses that of pristine CN (327.5 mu mol h(-1) g(-1)) by nearly 5-fold. Additionally, stability and recycling tests show the outstanding stability of the NvCN-3 photocatalyst over five cycles. This augmented performance is attributed to the small organic molecule-derived N-v engineering strategy, whereas N-v serves as electron-trapping sites that facilitate charge carrier separation, accelerate electron transport toward the platinum (Pt) cocatalyst, and ultimately boost the reduction of protons (H+) while hindering the charge recombination. This study introduces a simple and rational route for vacancy engineering to construct exceptionally effective CN-based photocatalysts for practical applications.

The binary metal sulfide Zn0.5Cd0.5S has emerged as a promising photocatalyst for hydrogen (H2) production via visible-light-driven water splitting. However, its practical application is limited by rapid charge carrier recombination and insufficient stability. In this study, nickel (II)-(3-pyridyl) benzimidazole (NPBIm) complexes were synthesized and employed an ultrasonic-assisted method to decorate the surface of Zn0.5Cd0.5S, forming a novel metal-complex semiconductor heterostructure system (Zn0.5Cd0.5S/NPBIm). This hybrid system significantly enhances photocatalytic H2 evolution under visible light irradiation. Experimental findings reveal that the incorporation of NPBIm molecules improves the optical absorption of Zn0.5Cd0.5S and facilitates more efficient separation and migration of photogenerated charge carriers. The optimized Zn₀.₅Cd₀.₅S/NPBIm hybrid heterostructure exhibits a remarkable hydrogen production rate of 272.22 µmol h⁻¹ under visible light irradiation (λ ≥ 420 nm), which is more than three times higher than that of pure Zn₀.₅Cd₀.₅S (92.54 µmol h⁻¹). This significant enhancement demonstrates the potential of combining semiconductor materials with metal-complex structures to improve photocatalytic performance. Furthermore, the hybrid photocatalyst exhibits excellent stability, an essential criterion for long-term energy applications. These findings highlight the effectiveness of integrating semiconductor materials with metal-complex structures to enhance photocatalytic performance. This study contributes to the advancement of solar-driven hydrogen production and offers a promising strategy for developing next-generation photocatalysts, with broader relevance to renewable energy and environmental sustainability.

Photocatalytic hydrogen (H2) evolution integrated with selective oxidation offers a prominent pathway for sustainable energy production and high-value chemical production. Metal sulfide-based photocatalysts (named MSP) have gained attention due to their appropriate band alignments, strong light absorption, and adjustable surface characteristics. This review systematically summarizes recent advances in MSP design for coupled H2 production and selective oxidation of representative organic molecules, including benzyl alcohol (BA), furfural alcohol (FFA), 5-hydroxymethylfurfural (HMF), benzylamine (BAm), and lactic acid (LA). Particularly, we highlight their photocatalytic performance and charge transfer mechanisms. Finally, this review presents current challenges and future strategies for designing efficient and industrially feasible photocatalytic systems.

A solar-driven hydrogen production process using a graphitic carbon nitride (CN) photocatalyst is an ideal future clean energy source. However, hydrogen production efficiency in the CN photocatalytic system is still limited due to rapid electron-hole (e-/h+) recombination. Herein, we report an efficient photocatalyst BCN-TPP by introducing 2,4,6-triphenylpyrylium (TPP) to boron-doped nitrogen-deficient carbon nitride (BCN) through pi-pi interaction and pi-cation interaction. The as-prepared photocatalyst shows increased visible light absorption and narrow band gap, enhancing the separation of photogenerated e(-)/h(+) pairs. TPP acts as a redox mediator under visible light excitation that can accept electrons from BCN, and then transfer them to the Pt cocatalyst. Photoluminescence (PL), electron paramagnetic resonance (EPR), and other electrochemical studies have exhibited that introducing a TPP mediator significantly enhances photogenerated charge carrier separation. BCN-TPP (10 wt % TPP) nanostructures achieved the photocatalytic H-2 generation rate of 110.33 mu mol h(-1) at visible light illumination (lambda >= 420 nm), which is 9.59 times higher than that of pristine C3N4 (11.50 mu mol h-1) and the apparent quantum efficiency (AQE) of 6.03% at 450 nm. Moreover, BCN-TPP shows the stability of H-2 evolution over 4 cycles without any significant decline. This study represents an approach for designing efficient nanoheterostructured photocatalysts for hydrogen production from water splitting.

In recent years, graphitic carbon nitride (g-C3N4) has attracted considerable attention because it includes earth-abundant carbon and nitrogen elements and exhibits good chemical and thermal stability owing to the strong covalent interaction in its conjugated layer structure. However, bulk g-C3N4 has some disadvantages of low specific surface area, poor light absorption, rapid recombination of photogenerated charge carriers, and insufficient active sites, which hinder its practical applications. In this study, we design and synthesize potassium single-atom (K SAs)-doped g-C3N4 porous nanosheets (CM-K-X, where X represents the mass of KHP added) via supramolecular self-assembling and chemical cross-linking copolymerization strategies. The results show that the utilization of supramolecules as precursors can produce g-C3N4 nanosheets with reduced thickness, increased surface area, and abundant mesopores. In addition, the intercalation of K atoms within the g-C3N4 nitrogen pots through the formation of K-N bonds results in the reduction of the band gap and expansion of the visible-light absorption range. The optimized K-doped CM-K-12 nanosheets achieve a specific surface area of 127 m(2) g(-1), which is 11.4 times larger than that of the pristine g-C3N4 nanosheets. Furthermore, the optimal CM-K-12 sample exhibits the maximum H-2 production rate of 127.78 mu mol h(-1) under visible light (lambda >= 420 nm), which is nearly 23 times higher than that of bare g-C3N4. This significant improvement of photocatalytic activity is attributed to the synergistic effects of the mesoporous structure and K SAs doping, which effectively increase the specific surface area, improve the visible-light absorption capacity, and facilitate the separation and transfer of photogenerated electron-hole pairs. Besides, the optimal sample shows good chemical stability for 20 h in the recycling experiments. Density functional theory calculations confirm that the introduction of K SAs significantly boosts the adsorption energy for water and decreases the activation energy barrier for the reduction of water to hydrogen.

A photoinduced photosensitizer-free Minisci-type reaction using aldehydes as radical precursors was reported, which showed excellent yields and functional groups tolerance. This effective method could achieve alkylation of natural products smoothly.

Plasmonic CN-NiMoN heterojunctions were prepared to enhance H 2 evolution from water splitting under visible-light ( λ ≥ 420 nm). Under visible-light irradiation, the optimal heterojunction shows 5.4 times higher activity than that of g-C 3 N 4 .

As a promising technology for highly pure hydrogen production under mild conditions, electrochemical water splitting has been garnering substantial interest, while its efficiency and rate are primarily restricted by the sluggish anodic oxygen evolution reaction (OER). To date, the most efficient electrocatalysts for the OER have been Ru or Ir-based nanomaterials, but features of high price, scarcity and instability limit their massive utilization in water splitting. Therefore, developing effective, inexpensive and stable electrocatalysts is critical for large-scale water splitting. In this review, the OER mechanisms were first discussed in detail and then the principles for designing advanced single atom-decorated transition metal oxide-based OER electrocatalysts with excellent activities and stabilities were proposed accordingly. After that, recent advances in designing and preparing single atom-decorated transition metal oxide-based OER electrocatalysts were summarized in terms of synthetic methods and intrinsic nature to enhance the OER. Meanwhile, the roles of atomically dispersed sites in transition metal oxides for OER performance improvement were presented. Finally, we also highlighted the key challenges and future opportunities of single atom-decorated transition metal oxide-based OER electrocatalysts to provide new insights into synthesizing low-cost transition metal oxide electrocatalysts for water splitting. Recent advances in designing and preparing single atom-decorated transition metal oxide-based OER electrocatalysts are summarized in terms of synthetic methods and intrinsic nature to enhance the OER.

Elemental doping is considered to be a promising approach for altering the electronic structure, optical absorbance, and charge separation characteristics of graphitic carbon nitride (g-C3N4, termed as CN), thus boosting its photocatalytic performance for practical applications. Herein, a series of boron (B) doped g-C3N4 (named as BCN) photocatalysts are developed via one-step pyrolysis of a mixture of urea and 3-methoxycarbonyl-5-nitriophenylboronic acid (MCNPBA). The results show that B-atoms have been successfully incorporated into the g-C3N4 network. The as-synthesized BCN-x (x shows the weight content of MCNPBA) photocatalysts are evaluated in photocatalytic hydrogen (H-2) evolution from water splitting under visible-light (lambda >= 420 nm). The optimized BCN-10 sample shows a maximum H-2 evolution rate of 1789.93 mu mol h(& horbar;1) g(& horbar;1), which is 6.2 times higher than that of g-C3N4 (289.73 mu mol h(& horbar;1) g(& horbar;1)). This is attributed to the fact that the electron-deficient B-atoms are lewis acids that trap electrons, which in turn expands visible-light absorption, narrows the bandgap, and prevents the recombination of photogenerated charge carriers. Moreover, B-doping can readily modify the valence and conduction band positions of g-C3N4, therefore augmenting the photocatalytic H-2 evolution activity. This paper presents a unique rational framework for developing other functionalized electron-deficient elemental-doping g-C3N4-based photocatalysts for practical applications in solar-to-fuel conversion.

Photoinduced carbamoylation of ethers using isocyanates asamide sources was accomplished under mild and environmentallyfriendly reaction conditions. A series of isocyanates were tolerated inthis protocol to construct alpha-amide-substituted ether derivatives withdesired yields. The method featured broad substrate scope and goodfunctional group tolerance, which could play an important role in theconstruction of biological molecules with ethers

The main existing issues in graphitic carbon nitride (g-C3N4) based photocatalytic hydrogen (H-2) production include poor separation and transfer of photogenerated charge carriers and low optical absorption. Thus, the construction of a multicomponent co-catalyst and its integration with g-C3N4 to facilitate the transport and separation of photoexcited charge carriers are regarded as a promising approach for augmenting the photocatalytic H-2 production activity. In this study, we report CoZnS@NSC-X/g-C3N4 (where X indicates sulfidation times of 15, 30, 45, and 60 min) nanocomposites constructed from a CoZn-MOF derived CoS2, Co3S4 and ZnS intercalated nitrogen/sulfur-doped carbon (CoZnS@NSC) nanoparticle co-catalyst and g-C3N4 for H-2 production from water splitting. The maximum photocatalytic H-2 evolution rate (610.8 mu mol h(-1) g(-1)) of the CoZnS@NSC-15/g-C3N4 heterostructure, with an optimized CoZnS@NSC loading of 10 wt% and 15 min sulfidation, is nearly 3.7 and 290.9 times higher than those of unsulfidated CoZn@NC/g-C3N4 and bare g-C3N4, respectively. This significantly boosted photocatalytic performance is attributed to the efficient separation and transfer of electron-hole (e(-)/h(+)) pairs and electronic conductivity caused by the appropriate sulfidation time and loading amount of CoZnS@NSC nanoparticles. This work offers a facile approach to designing metal-organic framework derived co-catalyst modified semiconductor-based photocatalysts for high-performance in practical applications.

In recent years, polymeric graphitic carbon nitride (g-C3N4 termed as CN) has emerged as a favorable candidate for solar energy conversion. However, its practical applications are limited due to rapid charge carrier recombination and poor visible-light absorption response. In this study, we report a simple one-step annealing strategy employing urea and l-aspartic acid (LAA) as precursors to prepare a series of carbon (C)-doped CN denoted as CCN-X, where X represents the nominal weight of LAA (X = 1, 4, 8, 12, and 16 mg). The results show that the introduction of C-atoms onto CN effectively improves visible-light absorption, narrows bandgap energy, and promotes the separation and transport of photogenerated electron-hole (e-/h+) pairs, culminating in a significantly higher photocatalytic hydrogen (H2) production from water splitting. The optimal CCN-8 sample achieves a maximum H2 production rate of 2192.2 mu mol h-1 g-1 under visible light (lambda >= 420 nm), which is 6.6 times higher than that of pristine CN (333.0 mu mol h-1 g-1). Additionally, the CCN-8 sample shows an apparent quantum efficiency (AQE) of 6.57% at 420 nm and outstanding photocatalytic stability of 16 hours during recycling tests. The doping of C-atoms into CN speeds up the transfer of holes (h+) to triethanolamine (TEOA) and electrons (e-) to a Pt cocatalyst, thus augmenting the visible-light photocatalytic H2 production from water splitting. This work provides a promising strategy for employing elemental doping to enhance semiconductor photocatalysts for efficient solar-driven H2 production.