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Based on the electron transfer behavior of H2O adsorption, H2O participates in the CO2 reduction in the form of *H species and H+ ions over F–In2O3(B) and NH2–In2O3(B) samples, respectively.

NO was adsorbed & activated at OVs over N-doped KNbO3, and then the formed N2O2− intermediates reacted with the ROS induced by visible light irradiation into NO2− and NO3−.

Sunlight-driven water splitting to produce hydrogen fuel has stimulated intensive scientific interest, as this technology has the potential to revolutionize fossil fuel-based energy systems in modern society. The oxygen evolution reaction (OER) determines the performance of overall water splitting owing to its sluggish kinetics with multielectron transfer processing. Polymeric photocatalysts have recently been developed for the OER, and substantial progress has been realized in this emerging research field. In this Review, the focus is on the photocatalytic technologies and materials of polymeric photocatalysts for the OER. Two practical systems, namely, particle suspension systems and film-based photoelectrochemical systems, form two main sections. The concept is reviewed in terms of thermodynamics and kinetics, and polymeric photocatalysts are discussed based on three key characteristics, namely, light absorption, charge separation and transfer, and surface oxidation reactions. A satisfactory OER performance by polymeric photocatalysts will eventually offer a platform to achieve overall water splitting and other advanced applications in a cost-effective, sustainable, and renewable manner using solar energy.

Photoelectrochemical (PEC) water splitting is an appealing approach by which to convert solar energy into hydrogen fuel. Polymeric semiconductors have recently attracted intense interest of many scientists for PEC water splitting. The crystallinity of polymer films is regarded as the main factor that determines the conversion efficiency. Herein, potassium poly(heptazine) imide (K-PHI) films with improved crystallinity were

The weak driving force and rapid carrier recombination severely restrict the development and utilization of piezocatalysis, but the important reason is the charge screening effect.

Photo-assisted Cu–Co/CeO2 in the Fischer–Tropsch synthesis to achieve high value-added alcohol production. Under light, the excited Cu and the electron transfer behavior of CeO2 promote the adsorption of CO and rapid hydrogenation.

In situ growth of crystalline carbon nitride on LaOCl with enhanced transfer and separation of photogenerated carriers for efficient photocatalytic overall water splitting.

A Au/TiO2-PD sample was prepared via a mild in situ photodeposition method followed by heat treatment. As compared to Au/TiO2-DP prepared by deposition precipitation, this Au/TiO2-PD sample owned the smaller sizes of Au nanoparticles (Au NPs), and exhibited a better catalytic activity for CO oxidation under visible light irradiation or otherwise. The results of XPS, in situ EPR and in situ DRIFTS tests indicated that TiO2 could transfer electrons to Au NPs caused the increase in surface electron density of Au NPs, resulting in the enhanced adsorption of CO at Au sites. This adsorbed CO could interact with the lattice O of TiO2 to form CO2 accompanied by oxygen vacancy, while O2 could be adsorbed at the oxygen vacancy to form the lattice O of TiO2 again. Moreover, the other oxygen atom of O2 adsorbed at oxygen vacancy may form activated O− species at adjacent Au sites, which can further react with another CO adsorbed at Au sites to form CO2. As compared with Au/TiO2-DP, the Au/TiO2-PD sample showed more electron transfer from TiO2 to Au sites (meaning more CO activation) and then the more activation of O2, resulting in an ultra-high activity of CO oxidation. Further, under visible light, the Au/TiO2-PD sample also exhibited a more obvious photopromoted effect due to the higher surface electron density of Au NPs induced by LSPR effect than Au/TiO2-DP. This study showed that the effect of Au NPs size on CO oxidation may somewhat be attributed to the electron transfer behavior.

China has promised to reach the peak carbon dioxide emission (ca. 10 billion tons) by 2030 and carbon neutrality by 2060. To realize these goals, it is necessary to develop hydrogen energy and fuel cell techniques. However, the high cost and low intrinsic safety of high-pressure hydrogen storage limit their commercialization. NH3 is high in hydrogen content, easily liquefied at low pressure, and free of carbon, and the technology of NH3 synthesis has been commercialized nationwide. It is worth noting that the production of NH3 in China is about 56 million tons per year, accounting for 35% of worldwide production. Hence, with the well established infrastructure for NH3 synthesis and transportation and the demand for clean energy in China, it is feasible to develop a green and economical energy roadmap, viz., “Clean low-pressure NH3 synthesis → Safe and economical NH3 storage and transportation → Carbon-free efficient NH3-H2 utilization”, for low-carbon or even carbon-free energy production. Currently, the academic and industrial communities in China are striving to make technological breakthroughs in areas such as photocatalytic water splitting, electrocatalytic water splitting, mild-condition NH3 synthesis, low-temperature NH3 catalytic decomposition, and indirect or direct NH3 fuel cells, with significant progress. Taking full advantage of the NH3 synthesis industry and readjusting the industrial structure, it is viable to achieve energy saving and emission reduction in NH3 synthesis industry (440 million tons CO2 per year), as well as promote a new energy industry and ensure national energy security. Therefore, relevant academic and industrial communities should put effort on mastering the key technologies of “Ammonia-Hydrogen” energy conversion and utilization with complete self-dependent intellectual property. It is envisioned that through the establishment of “Renewable Energy-Ammonia-Hydrogen” circular economy, a green technology chain for hydrogen energy industry would pose as a promising pathway to achieve the 2030 and 2060 goals.

Crystalline covalent organic frameworks (COFs) are porous polymeric semiconductors with network topologies, which are built from the integration of selected organic blocks with covalent bond linkages. They have shown great promise for artificial photosynthesis, owing to broad light harvesting, high crystallinity, and high carrier mobility. This Minireview introduces state-of-the-art COF photocatalysts based on different linkages and discusses the origin of photocatalytic activities for hydrogen evolution. Three typical COF photocatalysts, with linkages including imine (-C=N-), β-ketoenamine (O=C-C=C-NH-), and vinylene (-C=C-), are discussed with a particular focus on the advancements in synthetic methodologies and structural design, as well as photoelectronic properties that are relevant to photocatalytic performance. The Minireview is expected to elucidate their structure-property relationships and the way to design photoactive COFs with enhanced performances.

Photothermal catalysis is a widely researched field in which the reaction mechanism is usually investigated based on the photochemical behavior of the catalytic material. Considering that the adsorption of reactants is essential for catalytic reactions to occur, in this study, the synergistic effect of photothermal catalysis is innovatively elucidated in terms of the electron transfer behavior of reactant adsorption. For the H2 + O2 or CO + H2 reaction systems over a ZnO catalyst, UV irradiation at 25 °C or heat without UV irradiation did not cause H2 oxidation or CO reduction; only photothermal conditions (100 or 150 °C + UV light) initiated the two reactions. This result is related to the electron transfer behavior associated with the adsorption of CO or H2 on ZnO, in which H2 or CO that lost an electron could be oxidized by O2 or hydroxyls. However, the electron-accepting CO could be reduced by the electron-donating H2 into CH4 under photothermal conditions. Based on the in-situ characterization and theoretical calculation results, it was established that the synergistic effect of the photothermal conditions acted on the (002) crystal surface of ZnO to stimulate the growth of zinc vacancies, which resulted in the formation of defect energy levels, adsorption sites, and an adjusted Fermi level. As a result, the electron transfer behavior between adsorbed CO or H2 and the crystal surface varied, which further affected the photocatalytic behavior. The results show that the effect of photothermal synergy may not only produce the expected kinetic energy, but more importantly, produce energy that can change the activation mode of the reactant gas. This study provides a new understanding of the CO catalytic oxidation and reduction processes over semiconductor materials.

ZnO samples with different surface vacancy defects in nature were successfully synthesized via a hydrothermal method, and the correlation between the surface defects and photocorrosion was investig...

In this work, TiO2 was modified by doping the electron-deficient B element, and then the gas-sensing response of B-TiO2 to H2 under UV irradiation at room temperature in a N2 atmosphere and the oxidation of H2 over B-TiO2 under corresponding conditions were tested. It was found that H2 would accept an electron when adsorbed on the TiO2 surface, while H2 would donate an electron when adsorbed on the B-TiO2 surface. Correspondingly, H2 could not be oxidized over TiO2, but could be oxidized over B-TiO2. This indicated that the oxidation of H2 was dependent on the electron-transfer behavior between H2 and the surface of TiO2 or B-TiO2. Based on the relevant characterization results, it was proposed that H2 could accept an electron from TiO2 due to the higher Fermi level of TiO2, while H2 could donate an electron to B-TiO2 due to the lower Fermi level of B-TiO2 induced by doping B. This indicated that the electron-transfer behavior between H2 and TiO2 could be changed by adjusting the Fermi level of TiO2, while the electron-transfer behavior would further affect the photocatalytic activity of oxidizing H2. This result shows that the doable H2 photocatalytic oxidation in thermodynamics can be controlled by a kinetics factor (H2 losing-an-electron behavior). This work can be applied to provide an understanding of the photocatalytic oxidation behavior of other reactants over semiconductor materials.

In this work, CO2 and H2O were converted into C1–C2 over a Pd/Mn–TiO2 catalyst under a particular condition (heat, pressure, and illumination). It was found that only C1 was produced over Pd/Mn–TiO2 in thermal and pressure fields (180 °C and 3.5 MPa), but C2 (alcohol) was formed as a major product with the introduction of UV light. Based on the investigation results, it is proposed that the synergism between the Pd–Mn and TiO2 sites would be responsible for the alcohol product, where Mn acted as a reaction site for CO2 activation and C–C coupling to form C2 products. In addition, Pd mainly served as an electron collector that captured the light-excited electrons from TiO2 and transported them into Mn sites, resulting in a triggered C–C coupling at the given conditions. This study may provide a reliable approach for the conversion of CO2 into high-value chemicals.

Developing high-efficiency photocatalysts for CO2 photoreduction is one of the potential solutions to address both energy and pollution issues. In this study, α-Fe2O3 modified La2Ti2O7 was successfully synthesized with intimate contact between La2Ti2O7 and α-Fe2O3, greatly facilitating the carrier separation and transfer during the photocatalytic reaction. The activity and stability for photocatalytic CO2 reduction over α-Fe2O3/La2Ti2O7 were significantly improved as compared with the La2Ti2O7 substrate. The optimized 3% α-Fe2O3/ La2Ti2O7 composite showed excellent CO2 reduction activity after 5 h consecutive illumination, and the total utilized photoelectron number (UPN) reached 7.76 μmol, which was about 4.4 times higher than that of the pristine La2Ti2O7. The steady-state photoluminescence spectra, time-resolved photoluminescence spectra (TRPL) and photocurrent response results showed that the improved charge separation efficiency was the key factor to enhance the photocatalytic activity. This work provides novel insights into the design and fabrication of photocatalysts of high performance for CO2 reduction for solar-to-energy applications.

The design and synthesis of two semiconducting bis (4-ethynyl-bridging 1, 8-naphthalimide) bolaamphiphiles (BENI-COO- and BENI-NH3 + ) to fabricate supramolecular metal-insulator-semiconductor (MIS) nanostructures for biomimetic hydrogen evolution under visible light irradiation is presented. A H2 evolution rate of ca. 3.12 mmol g-1 ⋅h-1 and an apparent quantum efficiency (AQE) of ca. 1.63 % at 400 nm were achieved over the BENI-COO- -NH3 + -Ni MIS photosystem prepared by electrostatic self-assembly of BENI-COO- with the opposite-charged DuBois-Ni catalysts. The hot electrons of photoexcited BENI-COO- nanofibers were tunneled to the molecular Ni collectors across a salt bridge and an alkyl region of 2.2-2.5 nm length at a rate of 6.10×108 s-1 , which is five times larger than the BENI-NH3 + nanoribbons (1.17×108 s-1 ). The electric field benefited significantly the electron tunneling dynamics and compensated the charge-separated states insufficient in the BENI-COO- nanofibers.

Sun-light driven water splitting to produce hydrogen and oxygen gases in a large scale is a promising method for solar energy conversion. However, it is still a challenge to explore photocatalytic materials for overall water splitting due to the limited choice of a single semiconductor with suitable band energy levels (matching with water redox splitting potentials) while with minimized band gap for light harvesting. Here, we report a one-photon excitation pathway by coupling polymeric carbon nitride (PCN) with LaOCl semiconductor to achieve overall water splitting. This artificial photosynthesis composite catalyzes the decomposition of H2O into H2 and O2, with evolution rates of 22.3 and 10.7 µmol h-1, respectively, outperforming most of the PCN-based materials. The high photocatalytic performance of PCN/LaOCl can be ascribed to the simultaneously accomplished reduction and oxidation of water on LaOCl and PCN domains, respectively, as well as the fast charge separation and migration induced by the interfacial electric field related to LaOCl modification. This study provides new insights on the development of composite photocatalysts for pure water splitting on the basis of polymer-based materials via charge modulation.

The mild and sustainable methods for C–H direct trifluoromethylation of (hetero)arenes without any base or strong oxidants are in extremely high demand. Here, we report that the photo-generated electron-hole pairs of classical semiconductors (CdS or g-C3N4) under visible light excitation are effective to drive C–H trifluoromethylation of (hetero)arenes with stable and inexpensive CF3SO2Na as the trifluoromethyl (TFM) source via radical pathway. Either CdS or g-C3N4 propagated reaction can efficiently transform CF3SO2Na to [rad]CF3 radical and further afford the desired benzotrifluoride derivatives in moderate to good yields. After visible light initiated photocatalytic process, the key elements (such as F, S and C) derived from the starting TFM source of CF3SO2Na exhibited differential chemical forms as compared to those in other oxidative reactions. The photogenerated electron was trapped by chemisorbed O2 on photocatalysts to form superoxide radical anion (O2[rad]−) which will further attack [rad]CF3 radical with the generation of inorganic product F− and CO2. This resulted in a low utilization efficiency of [rad]CF3 (3SO2Na served as the starting materials in inert atmosphere, the photoexcited electrons can be directed to reduce the nitro group to amino group rather than being trapped by O2. Meanwhile, the photogenerated holes oxidize SO2CF3− into [rad]CF3. Both the photogenerated electrons and holes were engaged in reductive and oxidative paths, respectively. The desired product, trifluoromethylated aniline, was obtained successfully via one-pot free-radical synthesis.

Polymeric carbon nitrides (PCNs) are a species of metal-free semiconductors that consists of only Earth-abundant carbon and nitrogen elements. The semiconducting properties of PCN were first realiz...

The stoichiometric photocatalytic reaction of CO2 with H2O is one of the great challenges in photocatalysis. Here, we construct a Cu2O-Pt/SiC/IrOx composite by a controlled photodeposition and then an artificial photosynthetic system with Nafion membrane as diaphragm separating reduction and oxidation half-reactions. The artificial system exhibits excellent photocatalytic performance for CO2 reduction to HCOOH and H2O oxidation to O2 under visible light irradiation. The yields of HCOOH and O2 meet almost stoichiometric ratio and are as high as 896.7 and 440.7 μmol g−1 h−1, respectively. The high efficiencies of CO2 reduction and H2O oxidation in the artificial system are attributed to both the direct Z-scheme electronic structure of Cu2O-Pt/SiC/IrOx and the indirect Z-scheme spatially separated reduction and oxidation units, which greatly prolong lifetime of photogenerated electrons and holes and prevent the backward reaction of products. This work provides an effective and feasible strategy to increase the efficiency of artificial photosynthesis., The stoichiometric photoreaction of CO2 with H2O is one of the big challenges in photocatalysis. An artificial photosynthetic system based on a direct and indirect Z-scheme heterostructure is synthesised, enabling simultaneous CO2 reduction to HCOOH and H2O oxidation to O2.

The molecular mechanism of platinum-based drugs in concomitant chemoradiation therapy relies on enhancement of DNA damage in cancer cells, particularly that of detrimental clustered lesions and cross-links induced by the abundant low-energy electrons (LEEs) generated by ionizing radiation. We provide the complete 1-20 eV electron-energy dependence of the yields of all conformational LEE-induced lesions to biological DNA, when it binds to five molecules of the chemotherapeutic drug cisplatin. Recording at 1 eV intervals clearly show that the enhancement of all lesions is particularly intense at the energies of core-excited transient molecular anions (i.e., TMAs at 5, 6, and 10 eV). New TMAs are observed at 14 and 18 eV, only in yield functions of cisplatin-DNA complexes. Enhancements of all lesions by cisplatin are quantified over the 1-20 eV range, where maxima appear at 14 and 18 eV. The most detrimental lesions to cell survival exhibit the highest enhancements by factors of 2-3. Whereas no cluster lesions are induced by electrons of energy

Developing light-harvesting materials with broad spectral response is of fundamental importance in full-spectrum solar energy conversion. We found that, when a series of earth-abundant metal (Cu, Co, Ni and Fe) salts are dissolved in coordinating solvents uniformly dispersed nanodots (NDs) are formed rather than fully dissolving as molecular species. The previously unrecognized formation of this condensed state is ascribed to spontaneous aggregation of molecular transition-metal-complexes (TMCs) via weak intermolecular interactions, which results in redshifted and broadened absorption into the NIR region (200-1100 nm). Typical photoredox reactions, such as carbonylation and oxidative dehydrogenation, well demonstrate the feasibility of efficient utilization of NIR light (λ780 nm) by TMCs NDs. Our finding provides a conceptually new strategy for extending the absorption towards low energy photons in solar energy harvesting and conversion via photoredox transformations.

Treatment of recalcitrant landfill leachate (LFL) induces huge energy consumption and carbon emissions due to its complex composition. Although membrane distillation (MD) exhibits good potential in LFL treatment with waste heat utilization, membrane fouling and ammonia rejection are still the major problems encountered that hinder its application. Herein, membrane electrochemical reactor (MER) was coupled with MD for simultaneous membrane fouling control and resource recovery. LFL pretreatment with membrane-less electrochemical reactor (EO) and without pretreatment were also purified by MD for comparison. Results showed that the MER-MD system rejected almost all COD

D-π-A type 4-((9-phenylcarbazol-3-yl)ethynyl)-N-dodecyl-1,8-naphthalimide (CZNI) with a large dipole moment of 8.49 D and A-π-A type bis[(4,4'-1,8-naphthalimide)-N-dodecyl]ethyne (NINI) with a negligible dipole moment of 0.28 D, were smartly designed and synthesized to demonstrate the evidence of a molecular dipole as the dominant mechanism for controlling charge separation of organic semiconductors. In aqueous solution, these two novel naphthalimides can self-assemble to form nanoribbons (NRs) that present significantly different traces of exciton dissociation dynamics. Upon photoexcitation of NINI-NRs, no charge-separated excitons (CSEs) are formed due to the large exciton binding energy, accordingly there is no hydrogen evolution. On the contrary, in the photoexcited CZNI-NRs, the initial bound Frenkel excitons are dissociated to long-lived CSEs after undergoing ultrafast charge transfer within ca. 1.25 ps and charge separation within less than 5.0 ps. Finally, these free electrons were injected into Pt co-catalysts for reducing protons to H

This work reports the dehydrated Zr-based MOF UiO-66(SH)