Photocatalytic Hydrogen Generation Research Articles

Interfacial Bi–S chemical bond-coupled sulfur vacancy in Bi4NbO8Cl@ZnIn2S4−x S-scheme heterojunction for superior photocatalytic hydrogen generation

Strategies such as reducing charge transfer resistance and enhancing transmission driving force are considered effective in achieving higher photocatalytic performance. In this study, Bi4NbO8Cl@ZnIn2S4−x S-scheme heterojunction photocatalyst with atomic-level interface Bi–S chemical bond connection was successfully constructed through in-situ growth of ZnIn2S4−x nanosheets containing sulfur vacancies (Sv) on Bi4NbO8Cl microplates. Firstly, the S-scheme charge transfer mode effectively spatially separated photogenerated carriers while retaining their reactivity to the maximum extent. Secondly, the interfacial Bi–S bond served as a “bridge” to lessen the interface resistance and provide a high-speed channel for the transmission of photogenerated carriers. Lastly, Sv effectively expanded the Fermi level (Ef) difference between the two semiconductors in the heterojunction, so as to enlarge the built-in electric field (IEF) at the interface and reinforce the driving force for charge transfer. Owing to the synergistic effects of these advantages, the Bi4NbO8Cl@ZnIn2S4−x composite exhibited an average hydrogen production rate of up to 8.7 mmol g−1h−1 under visible light, which was 4.0 and 14.5 times that of ZnIn2S4−x and Bi4NbO8Cl samples, respectively. This work presents a novel approach for designing interfacial chemically bonded S-scheme heterojunction photocatalysts with high catalytic activity.

Gallic acid assisted synthesis of novel CuO/Ni/Fe3O4 nanocomposite for catalytic CO2 methanation and photocatalytic hydrogen generation

Gallic acid assisted synthesis of novel CuO/Ni/Fe3O4 nanocomposite for catalytic CO2 methanation and photocatalytic hydrogen generation

Enhancing photocatalytic hydrogen generation by achieving long-lasting shallow trapping states in distorted covalent triazine frameworks

Short-lived shallow trapping states in photocatalysts created from polymeric semiconductors impedes the effective use of charge carriers, leading to a decrease in the solar-to-hydrogen conversion efficiency of covalent triazine frameworks (CTF). In this study, methylene-modified covalent triazine frameworks (M−CTF) with increased structural distortion were synthesized through a dynamic trimerization reaction of cyano groups using the precursors of 1,4-terephthalonitrile and 1,4-phenylenediacetonitrile. The optimal M−CTF catalyst obtained in this approach showed persistent shallow trapping states through n-π* electronic transitions, leading to a noticeable red-shift in the light absorption edge to 600 nm. Femtosecond transient absorption spectroscopy verified the existence of shallow trapping states with extended lifetimes (1103.8 ps) in M−CTF. The distorted structure promote increased involvement of photo-induced electrons in reducing water to generate H2, leading to a substantial improvement in the ability of M−CTF to catalyze the production of H2. M−CTF sample loaded with Pt cocatalysts exhibited an impressive efficiency of 10.1 mmol·g−1·h −1 in producing H2 via photocatalysis under visible light (λ > 420 nm), marking a tenfold improvement compared to the original CTF. The findings underscore the significance of structural distortion in CTF for achieving long-lasting shallow trapping states, leading to improved photocatalytic efficiency.

Efficient Photocatalytic Hydrogen Production Using In-Situ Polymerized Gold Nanocluster Assemblies.

Gold nanoparticles (NPs) are widely recognized as co-catalysts in semiconductor photocatalysis for enhancing hydrogen production efficiency, but they are often overlooked as primary catalysts due to the rapid recombination of excited-state electrons. This study presents an innovative gold-based photocatalyst design utilizing an in situ dopamine polymerization-guided assembly approach for efficient H2 generation via water splitting. By employing gold superclusters (AuSCs; ≈100nm) instead of ultra-small gold nanoclusters (AuNCs; ≈2nm) before polymerization, unique nanodisk-like 3D superstructures consisting of agglomerated 2D polydopamine (PDA) nanosheets with a high percentage of uniformly embedded AuNCs are created that exhibit enhanced metallic character post-polymerization. The thin PDA layer between adjacent AuNCs functions as an efficient electron transport medium, directing excited-state electrons toward the surface and minimizing recombination. Notably, the AuSCs@PDA structure shows the largest potential difference (26.0mV) compared to AuSCs (≈18.4mV) and PDA NPs (≈14.6mV), indicating a higher population of accumulated photo-generated carriers. As a result, AuSCs@PDA achieves a higher photocurrent density, improved photostability, and lower charge transfer resistance than PDA NPs, AuSCs, or AuNCs@PDA, with the highest hydrogen evolution rate of 3.20mmol g-1h-1. This work highlights a promising in situ polymerization strategy for enhancing photocatalytic hydrogen generation with metal nanoclusters.

Fluoro-polymer/TiO2 based photocatalysts for high efficiency hydrogen generation

In view of limited number of studies on photoreforming of synthetic polymers, herein, a series of new glycopolymers are synthesized via RAFT polymerization to obtain diblock copolymers containing fluorinated and non-fluorinated segments in the glucopyranoside. These glycopolymers are used as probes to investigate photocatalytic reactions at different pH values of the modulated TiO2 photocatalyst. Through structural and surface characterizations, photocatalytic activities are investigated. Fluoro-polymers with deacetylated glucose, hydrophilic segment, PGD such as PPFPM-b-PGD and PPFBM-b-PGD could synergistically increase hydrogen generation rate up to 1368 μmol g-1h−1 and 1549 μmol g-1h−1 with quantum yields of 3.34 % and 3.79 % compared to non-fluoro glycopolymers. The presence of both fluorinated and non-fluorinated groups in diblock copolymers enhanced the rate of photocatalytic hydrogen generation compared to the homopolymer. The accelerated photo-reforming is attributed to in-situ fluorine-doped TiO2 along with high affinity and activation of water molecules. These polymers can generate hydrogen via photo-reforming process.

Boosting photocatalytic hydrogen generation and Photo-Destruction of Tetracycline by In-Situ oxygen vacancies ZnIn2S4

In this study, ZnIn2S4 with oxygen vacancies was fabricated using NaBH4-assisted hydrothermal method to enhance the photocatalytic activities. The generated ZIS and ZISVo-x samples exhibited microspherical nanosheet structure and it is proven that NaBH4 could enhance the amount of oxygen vacancies in ZnIn2S4 as confirmed by XPS analysis. Upon solar light irradiation, ZISVo-5 sample performed a fast photodegradation of tetracycline (TC) within 10 min and simultaneously exhibited a hydrogen evolution amount of ∼ 12 mmol (AQE = 6.07 at 420 nm), which is 2.75 times higher than that of pristine ZnIn2S4 (4.4 mmol). The degraded products of TC were further identified using LC-MS. The excellent photocatalytic HER performance was attributed to the optimum amount of oxygen vacancies in ZISVo-5 sample and the reactive oxygen species of •OH, O2•-, and 1O2 as confirmed by ESR analysis under light irradiation played a vital role for the rapid degradation of TC by ZISVo-5.

Introducing built-in electric field and spatially separated reactive sites in asymmetric crystalline g-C3N4 for robust photocatalytic hydrogen generation

Constructing arobust internal electric field within photocatalysts is a crucial strategy for propelling the reverse migration of photocarriers and ensuring theeffective occurrence of respective reduction and oxidation reactions. Herein, we synthesized a crystalline g-C3N4 with anasymmetrical structure via introducing a small molecule 2-aminopyrimidine-4,6-diol (AP) and cyano groups on heptazine ring units. The optimized sample (ACNM-3) is endowed with an uneven distribution of charge density and a large dipole moment, thus forming a built-in electric field, which is beneficial for charge separation and migration in space. In-situ XPS and DFT theoretical calculations demonstrate that Pt acts as the reduction site loaded on the inserted AP and the C site of its adjacent heptazine ring, while the oxidation sites are around the heptazine rings containing the cyano groups and the N sites of its adjacent heptazine rings. Such spatially separated redox sites enable ACNM-3 to continuously and robustly trigger proton reduction and TEOA oxidation reactions. Thus, ACNM-3 exhibits an outstanding and stable photocatalytic H2 production rate ofup to 14.19 mmol/g/h, which is over 16 times that of bulk g-C3N4. This work provides a synergistic strategy of internal electric field and catalytic site modulation to synthesize efficient and robust photocatalysts, illuminating the way for the application of photocatalytic H2 production.

Effective photocatalytic hydrogen generation and degradation for single cobalt and tungsten metal atom oxide anchored on titanium dioxide-bismuth molybdate-reduced graphene oxide

A simple hydrothermal method was used to prepare the single-metal atom oxide (SMAO) catalyst. The prepared dual Cobalt and tungsten (CoW) single metal atom oxide anchored on the TiO2-Bi2MoO6-reduced graphene oxide (rGO), an interstitial atomic line of tungsten and cobalt. The prepared photocatalyst showed good photocatalytic hydrogen (H2) evolution and organic contaminant degradation. As co-catalysts, surface-dispersed CoW sites were created using a Co mono-substituted hetero-polyacid (HPA-Co). A larger quantity of single atoms were uniformly decorated on the TiO2-Bi2MoO6-Ethylenediamine (ED)-rGO catalyst. The presence of the CoW species was verified employing extended X-ray absorption near edge structure (XANES), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and extended X-ray absorption fine structure (EXAFS) analyses after a TiO2-Bi2MoO6-CoW-ED-rGO composite synthesized. The findings demonstrate that TiO2-Bi2MoO6-CoW-ED-rGO catalysts were more capable of producing hydrogen and degrading Ciprofloxacin (CIP) (21.46 mmol/g/h, 97.2%) than other bare and binary catalysts. Furthermore, it showed remarkable stability and reusability after five consecutive CIP photodegradation and H2 production cycles. Gas chromatography/mass spectroscopy (GC/MS) techniques were used to identify the intermediates in the photodegradation process. The prepared photocatalyst was significantly increased, and the separation of charge carriers was further boosted, thanks to the CoW material and the synergistic effect. A possible Z-scheme mechanism was proposed for the photocatalytic H2 production activity. More electrons can contribute to the reduction of H2 evolution because of the processability of the Z-scheme. This work created a recyclable, inexpensive, highly effective, and non-toxic catalytic material for H2 generation and CIP degradation.

Joint Electrons and Photons Transfer from Dual‐Functional WO3:Yb,Er to Zn0.5Cd0.5S for Efficient H2 Evolution

AbstractUtilization of the near‐infrared (NIR) light in the solar spectrum is critical for efficiency improvement of photocatalytic H2 evolution. However, common semiconductors have low response to the NIR light and narrow bandgap semiconductors have inappropriate redox potentials. Here, the study presents a new dual‐functional up‐conversion strategy in one sensitizer for promoting photocatalytic hydrogen production reactions by converting NIR light to visible light and high‐energy electrons simultaneously, via photon‐photon conversion and photo‐electronic process, respectively. Using WO3:Yb,Er as the sensitizer and Zn0.5Cd0.5S as the hydrogen evolution reaction catalyst, a photocatalytic hydrogen release rate of 24.3 mmol g−1 h−1 under simulated solar‐light has been achieved without using any co‐catalyst. After loading Ni2P as a co‐catalyst, the photocatalytic hydrogen production performance can be further improved to 41.3 mmol g−1 h−1 at 10 °C and 93.3 mmol g−1 h−1 under non‐temperature‐controlled conditions, exceeding most photocatalysts. This work offers a new strategy to improve the NIR light utilization of the solar‐light for promoting photocatalytic hydrogen generation through synergistic photo‐optical, photo‐electronic, and photo‐thermal effects.

Unveiling ternary NiS@NC/CdS heterojunction synergistically induced superior photo/electrocatalytic hydrogen evolution

Herein, a ternary NiS@NC/CdS heterojunction is designed and synthesized by in situ depositing CdS on the hierarchical flower-like NiS2@NC derived from porous Ni-ZIF template for a superior photo/electrocatalytic hydrogen evolution. The findings reveal that the introduced Cd atoms could react with S atoms from NiS2 to form CdS, and meantime the original NiS2 crystal phase transforms into a new NiS phase, which results in tight contact between CdS and NiS, and further facilitates efficient formation of ternary heterojunction among CdS, NiS and N doped porous carbon. As a result, the synthesized ternary NiS@NC/CdS heterojunction exhibits a superior photocatalytic hydrogen generation activity, up to 15.4 mmol/gcat in 3 hours, in the absence of Pt cocatalyst, which is 2.3 and 230 times higher than that of NiS2@NC and CdS, respectively. The results demonstrate that the introduction of CdS can efficiently enhance the production of photogenerated carriers, and the presence of ternary heterojunction can further improve the separation and transportation efficiency of photogenerated carriers. Moreover, density functional theory (DFT) calculations demonstrate that the presence of CdS and carbon efficiently reduces the adsorption energy of H*, leading to a significant enhancement of hydrogen evolution performance. This work provides a new perspective for improving the photo/electrocatalytic activity of MOFs-derived carbon materials.

Emerging Trends in CdS-Based Nanoheterostructures: From Type-II and Z-Scheme toward S-Scheme Photocatalytic H2 Production.

Cadmium sulfide (CdS) based heterojunctions, including type-II, Z-scheme, and S-scheme systems emerged as promising materials for augmenting photocatalytic hydrogen (H2) generation from water splitting. This review offers an exclusive highlight of their fundamental principles, synthesis routes, charge transfer mechanisms, and performance properties in improving H2 production. We overview the crucial roles of Type-II heterojunctions in enhancing charge separation, Z-scheme heterojunctions in promoting redox potentials to reduce electron-hole (e-/h+) pairs recombination, and S-scheme heterojunctions in combining the merits of both type-II and Z-scheme frameworks to obtain highly efficient H2 production. The importance of this review is demonstrated by its thorough comparison of these three configurations, presenting valuable insights into their special contributions and capability for augmenting photocatalytic H2 activity. Additionally, key challenges and prospects in the practical applications of CdS-based heterojunctions are addressed, which provides a comprehensive route for emerging research in achieving sustainable energy goals.

Noble-metal-free Bi-OZIS nanohybrids for sacrificial-agent-free photocatalytic water splitting: With long-lived photogenerated electrons

The production of hydrogen via the hydrogen evolution reaction, reliant on the use of valuable sacrificial agents, is not conducive to large-scale photocatalytic hydrogen generation. A more pragmatic approach involves the creation of catalyst materials free from noble metals, which possess enduring photogenerated electrons suitable for catalyzing hydrogen evolution from undiluted water. In our research, x%Bi-OZIS nanohybrids were effectively synthesized. Remarkably, the hydrogen evolution rate for the 10 %Bi-OZIS sample reached 170.22 μmol g-1h−1, marking an enhancement of 11.8 times over pure ZIS and 3.7 times over OZIS, achieved without resorting to sacrificial agents. Notably, post-light exposure, H2O2 presence was identified in the water solution. The strategy of substituting some of the sulfur with oxygen doping extends the lifespan of the photogenerated carriers. Further, the introduction of Bi spheres onto the OZIS nanosheet surfaces substantially reduces electron-hole interband recombination. These adaptations collectively augment the photogenerated electron lifespan in x%Bi-OZIS nanohybrids, leading to heightened photocatalytic redox proficiency. This research outlines a method for devising an economical solar-driven water splitting mechanism devoid of sacrificial agents.

Cobalt and tungsten single-metal atom catalyst coupled with TiO2–BiCu2VO6 metal oxide on the graphene for efficient solar fuel production and chromium reduction

There is immense promise in photocatalysis for utilizing single-atomic-layer cobalt and tungsten oxide (CoW) on TiO2–BiCu2VO6, ethylene diamine, and reduced graphene-oxide-supported materials. Although there is great excitement surrounding single-metal atom oxide catalysts, converting bulk metal oxides into single-atom oxides remains challenging. In addition, creating high-performance materials for photocatalytic hydrogen (H2) generation and Cr(VI) reduction is crucial and challenging. This work presents a precise catalyst achieved by anchoring a high loading of CoW single metal atom oxide onto the surface of TiO2–BiCu2VO6-rGO through a simple sonication process, even at low temperatures. The prepared TiO2–BiCu2VO6–CoW-ED-rGO (TBCR) catalysts exhibited improved stability when used for hydrogen (H2) generation and Cr(VI) reduction under visible-light illumination. The single Co and W atoms on the TiO2–BiCu2VO6 catalyst demonstrated exceptional performance in H2 generation and Cr(VI) reduction. Through careful experimentation, optimizing the loading of single atoms on the interstitial atomic line of TiO2–BiCu2VO6 significantly enhanced its visible-light absorption capabilities. Using HAADF-STEM, EXAFS, and XANES investigations, cobalt/tungsten single metal atom oxide was determined to be uniformly dispersed over the TiO2–BiCu2VO6 material. The developed photocatalyst showed impressive results with improved H2 generation (36.48 mmol/g/h) and maximum reduction of Cr(VI) (99.4 %). Moreover, by harnessing solar radiation, the photocatalyst can efficiently replace existing noble metal catalysts as a highly effective and durable single-atom catalyst for renewable H2 generation and Cr(VI) reduction.

Investigation of kinetic mechanisms of photocatalytic hydrogen generation from formic aside using metal-ceramic composites under visible-light irradiation

Processes of photocatalytic hydrogen generation from the formic acid water solution under vis-light irradiation with tantalum contained metal-ceramic silicon nitride-based composites were investigated depending on pH of the solution and hydrogen peroxide adding. These compounds were obtained by self-propagated high temperature (SHS) synthesis in the way of the ferrosilicoaluminum (FSA) and silicon-aluminum powders ignition in a nitrogen atmosphere with the tantalum addition. During the investigation it was found out that the reaction rate of the hydrogen production without hydrogen peroxide can be described within the Langmuir–Hinshelwood mechanism. There is the reaction mechanism changing simultaneously with a formic acid concentration increasing in the presence of H2O2. The most significant reaction rate of hydrogen production from HCOOH is observed with the Fe-contained composite synthesized from FSA in the solution system without H2O2 addition, the reaction turns of frequency (TOF) is 4.55 µmol/min.

Square-Planar Nickel Bis(phosphinopyridyl) Complexes for Long-Lived Photocatalytic Hydrogen Evolution.

Phosphinopyridyl ligands are used to synthesize a class of Ni(II) bis(chelate) complexes, which have been comprehensively characterized in both solid and solution phases. The structures display a square-planar configuration within the primary coordination sphere, with axially positioned labile binding sites. Their electrochemical data reveal two redox couples during the reduction process, suggesting the possibility of accessing two-electron reduction states. Significantly, these complexes serve as robust catalysts for homogeneous photocatalytic H2 evolution. In a system utilizing an organic photosensitizer and a sacrificial electron donor, an optimal turnover number of 27,100 is achieved in an alcohol-containing aqueous solution. A series of photophysical and electrochemical measurements were conducted to elucidate the reaction mechanism of photocatalytic hydrogen generation. Density function theory calculations propose a catalytic pathway involving two successive one-electron reduction steps, followed by two proton discharges. The sustained photocatalytic activity of these complexes stems from their distinct ligand system, which includes phosphine and pyridine donors that aid in stabilizing the low oxidation states of the Ni center.

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.

Synergistic effects of MXene support and cobalt salts in dye-sensitized photocatalytic hydrogen generation

This study introduces an approach to photocatalytic hydrogen production through a dye-sensitized photocatalytic system employing MXene (Ti3C2Tx) and a non-noble cobalt metal catalyst. It was demonstrated that simple integration of eosin Y, Ti3C2Tx and cobalt salt (CoSO4) significantly enhances the photocatalytic hydrogen evolution, outperforming the corresponding system that does not include Ti3C2Tx. The key to this enhanced performance lies in the unique properties of MXene material, which facilitates effective electron transfer and acts as a support for dye and catalyst. The successful well-dispersed decoration of small (2–3 nm) cobalt-based nanoparticles on the Ti3C2Tx sheet via in situ photodeposition was confirmed by transmission electron microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). The optimal hydrogen production rates were achieved with a Co to Ti3C2Tx mass ratio of 15%. This optimized interaction results in a hydrogen evolution rate of 40.1 mmol h−1 g−1 and an apparent quantum efficiency (AQE) of 35.4% at 505 nm. These findings highlight the potential of Ti3C2Tx as a versatile component in photocatalytic systems, particularly effective when paired with economically viable, earth-abundant catalysts like cobalt.

Photo- and Electrocatalytic Hydrogen Evolution by Heteroleptic Dirhodium(II,II) Complexes: Role of the Bridging and Diimine Ligands.

A series of heteroleptic Rh2(II,II) complexes, cis-[Rh2(μ-DPhF)2(μ-bncn)2]2+ (1; bncn = benzo[c]cinnoline), cis-[Rh2(μ-DPhF)(μ-OAc)(μ-bncn)2]2+ (2), and cis-[Rh2(μ-OAc)2(μ-bncn)2]2+ (3), is presented, and the excited state and redox properties of each complex was characterized for the photo- and electrocatalytic production of H2. The oxidation potentials shift anodically from 1 to 3, consistent with a highest occupied molecular orbital (HOMO) with significant metal-ligand mixing, Rh2(δ*)/DPhF(π/nb). In contrast, modest differences in the first two bncn-localized reversible reduction potentials were observed in 1 - 3. The lowest energy metal/ligand-to-ligand charge transfer (1ML-LCT) transition, Rh2(δ*)/DPhF(π/nb) → bncn(π*), shifts from 633 nm in 1 to 553 nm in 2, and the metal-to-ligand charge transfer (1MLCT) Rh2(π*) → bncn(π*) absorption in 3 appears at 462 nm in CH3CN. Although the 3ML-LCT excited state of 2 is shorter lived than that of 1, 2.7 ns as compared to 19 ns, respectively, photocatalytic hydrogen generation is observed for the former upon 595 nm irradiation in the presence of 0.1 M TsOH (p-tolylsulfonic acid) and 0.1 M BNAH (1-benzyl-1,4-dihydronicotinamide). The temperature dependence of the 3ML-LCT lifetimes of 1 and 2 shows the presence of a thermally accessible deactivating state. In addition, the singly reduced intermediate, [2]-, is photoactive and able to generate hydrogen in the presence of TsOH. Importantly, the electrocatalytic currents generated by equimolar concentrations of 1 - 3 in CH3CN are nearly identical, consistent with a mechanism of catalysis that is localized on the bncn ligand and does not require a Rh-H hydride intermediate. This finding can be used to develop earth-abundant first-row transition metal complexes for photo- and electrocatalytic H2 production.

Recent progress of MoS2 for photocatalytic and electrocatalytic hydrogen generation—A review

Recent progress of MoS2 for photocatalytic and electrocatalytic hydrogen generation—A review

Ag2Se nanoparticles anchored on S-g-C3N4 nanosheets towards efficient photocatalytic tetracycline hydrochloride removal and H2 generation

To improve the stability of Ag based co-catalysts and to increase the photocatalytic performance of graphitic carbon nitride (g-C3N4), Ag2Se nanoparticles were grown onto superior thin sulfur-doped g-C3N4 nanosheets which was fabricated via two-step thermal polymerization at high temperature. Ultrathin S-doped g-C3N4 nanosheets were prepared via two-step thermal polymerization using melamine and thiourea. The ratios of Ag2Se were adjusted to fabricate a series of Ag2Se/S-g-C3N4 (Ag2Se/SCN) composite samples by controlled solvothermal synthesis. S-doping plays an important role in mono-dispersion of Ag2Se nanoparticles on S-g-C3N4 nanosheets because of the control of growth sites. The photocatalytic removal of tetracycline hydrochloride test indicates that sample Ag2Se/SCN-3 with Ag2Se loading of 3 % reveals the best removal effect, in which tetracycline hydrochloride of 60 % is removed within 60 min. Photocatalytic hydrogen generation test results without co-catalyst addition demonstrate that sample Ag2Se/SCN-3 exhibits the best H2 evolution rate of 2116.35 μmol·g−1·h−1, which is 3.8 times of that of pure carbon nitride. The photocatalytic mechanism tests suggest that Schottky heterojunctions are formed in the Ag2Se/S-g-C3N4 composites. The formation of Schottky heterojunctions improved the separation efficiency of photogenerated charge carriers. The incorporation of Ag2Se nanoparticles (as the co-catalyst) on S-g-C3N4 nanosheets is the key for drastically improving the photocatalytic performance and eliminating the use of Pt co-catalyst during the photocatalytic processes.