So far, achieving high apparent quantum yield (AQY) in polymeric photocatalysts at wavelengths up to 500 nm has never been achieved. Covalent organic polymers (COPs) have the advantage of high structure function tunability. However, despite decades of development, COPs still lag in achieving high AQY value, highlighting the need for an optimal COP structural design for efficient photocatalysis. Herein, we present a green synthetic approach to synthesize five hydrophilic and non-conjugated linkage with D-π-A system benzoin-based COPs by self-condensation of multiformly monomers. Charge kinetic carrier and femtosecond transient absorption (fs-TAS) demonstrate the efficient charge transport of benzoin-based COPs. Among the synthesized photocatalysts, B-PyTT-COP (D-π-A) outperforms the COP family, with an excellent HER of 233.81 µmol h⁻¹ (77935 µmol g⁻¹h⁻¹) using Platinum as co-catalyst. Remarkedly, B-PyTT-COP has achieved an exceptional ability to generate a high AQY value at 500 nm (65.35 %), surpassing all other materials examined thus far.

Photocatalytic hydrogen production through water splitting provides a promising route towards renewable energy generation. However, constructing photocatalytically active covalent organic frameworks with high charge separation remains challenging. Herein, we demonstrate for the first time the use of 2D imide–imine-based covalent organic frameworks as new photocatalysts for the hydrogen evolution reaction (HER) under visible light irradiation. The main achievement is incorporating donor and dual acceptors, including weak electron-deficient imine and strong electron-deficient imide groups within the 2D COF backbone that create favorable push–pull–pull intramolecular charge transfer to promote charge separation after photoexcitation. DFT and NBO calculations revealed the strong integration of donor and dual acceptors with a synergistic interplay enhancing spatial charge transfer and separation. The synthesized COFs show significantly high thermal stability >400 °C with a high energy barrier for degradation. Moreover, Py-DNII-COF exhibited a 104-fold enhancement in hydrogen evolution compared to TFPB-DNII-COF. Py-DNII-COF demonstrated excellent stability and hydrogen evolution of 625 μmol h⁻¹ g⁻¹ over 48 hours.

Background: Conjugated microporous polymers (CMPs) have been applied widely in several energy storage applications. Triphenylamine derivatives are good electrode materials that can be processed into SC devices because of their high charge mobilities, unique electronic properties, and high redox activity. Methods: We prepared two novel tetrabenzonaphthalene-linked conjugated microporous polymers (TBN-pH CMPs) through [4 + 2] and [4 + 3] Schiff-base condensations of 2,7,10,15-tetra(4-formylphenyl)tetrabenzonaphthalene (TBN-PhCHO) with tetrakis(4-aminophenyl)ethene (TPE-4NH2) and tris(4-aminophenyl)amine (TPA-3NH2), respectively. Fourier transform infrared, and solid-state 13C NMR spectroscopy investigated the structures of the as-prepared CMPs. Significant Findings: These CMPs, had large surface areas and outstanding thermal stability at temperatures of up to 400 ◦C, making them suitable for use as electrodes in supercapacitor (SC) systems. Indeed, the TBN-TPA CMP–based electrode had high specific capacitances (251 F g − 1 measured at 0.5 A g–1 ) and capacity retentions (94%, measured after 5000 cycles at 10 A g–1 ) when tested in three-electrode systems. We attribute the remarkable electrochemical activity and conductivity of the TBN-TPA CMP electrode to its large specific surface area (230 m2 g–1 ) and chemical structure featuring stacking of the benzene rings of its redox-active triphenylamine moieties.

Various energy storage systems widely utilizeconjugated microporous polymers (CMPs) due to their porousarchitecture and expansive surface area, which facilitate efficient iontransport and storage. In our research, we developed twoanthraquinone (ATQ)-based CMPs (ATQ-CMPs) through aSonogashira coupling method. We used 2,6-dibromoanthraquinone(ATQ-Br2), a redox-active precursor, as a building monomer alongwith an ethynyl derivative of triphenylamine (TPA-T) andtetrabenzonaphthalene (TBN-T) to afford TPA-ATQ CMP andTBN-ATQ CMP, respectively. We employed techniques, such asthermogravimetric analysis, high-resolution transmission electronmicroscopy (HR-TEM), scanning electron microscopy (SEM), andFourier-transform infrared spectroscopy (FTIR), to characterizethe structure and thermal properties of these ATQ-CMPs. The TBN-ATQ CMP displayed extensive Brunauer−Emmett−Teller(BET) surface areas (SBET = 161 m2 g−1) and remarkable thermal stability (temperatures of up to 605 °C). These properties made itan excellent candidate for supercapacitor (SC) electrode materials. The electrodes fabricated using the TBN-ATQ CMP exhibited anexceptionally significant specific capacitance of 393 F g−1 when tested at a current density of 1 A g−1. After 5000 cycles at 10 A g−1,TBN-ATQ CMP still had 74.2% capacitance in a three-electrode setup. We also made a symmetrical device using the TBN-ATQCMP. This device had a capacitance of 175 F g−1 at 1 A g−1 and was very stable over 2000 cycles, keeping 92.8% of its capacitance.The TBN-ATQ CMP electrode has better electrochemical performance because it has a redox-active ATQ unit and high SBET. Ourfindings pave the way for simple methods of developing and producing efficient CMP materials using TBN and ATQ for high-performance SCs in both three- and two-electrode configurations

Single-atom-supported metal oxides have attracted extensive interest in energy catalysis, offering a promising avenue for mitigating greenhouse gas emissions and environmental pollution. This study presents a facile synthesis of single-atom Fe-modified Bi₂WO₆ photocatalysts. By carefully tuning the Fe ratios, the 1.5Fe-Bi₂WO₆ sample demonstrates exceptional photocatalytic efficiency in CO₂ to CO reduction (36.78 μmol g⁻¹). Additionally, an outstanding NO removal performance is also achieved through this photocatalyst with an impressively low conversion of toxic NO₂ at just 0.37%. The reaction intermediates and mechanisms governing the photocatalytic reduction of CO₂ into CO are elucidated using in situ DRIFTS and in situ XAS techniques. Regarding NO removal, the introduction of Fe single-atoms, along with induced oxygen vacancies, plays a pivotal role in facilitating the transformation of NO and NO₂ into nitrate by stabilizing NO and NO₂ species. Mechanistic insights into photocatalytic NO oxidation are garnered through scavenger trapping and EPR experiments employing DMPO. This study emphasizes single-atom-supported metal oxide's potential in sustainable chemistry and air purification, providing a promising solution for urgent environmental challenges.

Solar-driven CO₂ reduction holds great promise for sustainable energy, yet the role of atomic active sites in governing intermediate formation and conversion remains poorly understood. Herein, a synergistic strategy using Ni single atoms (SAs) and surface oxygen vacancies (O_v) is reported to regulate the CO₂ reduction pathway on the Bi₂WO₆ photocatalyst. Combining in-situ techniques and theoretical modeling, the reaction mechanism and the structure-activity relationship is elucidated. In-situ X-ray absorption spectroscopy identifies Bi and Ni as active sites, and in-situ diffuse reflectance infrared Fourier transform spectroscopy demonstrates that adsorption of H₂O and CO₂ readily forms CO₃²⁻ species on the O_v-rich catalyst. Optimally balancing Ni SAs and O_v lowers the energy barrier for the formation and dehydration of a key COOH intermediate, leading to favorable CO formation and desorption. Consequently, a superior CO production efficiency of 53.49 µmol g^‒1 is achieved, surpassing previous reports on Bi₂WO₆-based catalysts for gas-phase CO₂ photoreduction.

Conjugated microporous polymers (CMPs) have gained increased significance as crucial components in the field of photocatalytic H₂ production due to their excellent ultraviolet-visible (UV-vis), and robust fluorescence. Herein, we used two types of reaction approaches including Suzuki and Sonogashira–Hagihara coupling to prepare six different types of CMPs for the first time to investigate and understand the reactivity of triphenylamine (TPA) and alkyne group linked CMPs for photocatalytic H₂ evolution from H₂O. Six different TPA-based CMPs including TPA–TPA (D–D), TPE–TPA (A–D), Py–TPA (A–D), TPA–TB–TPA (D–π–D), TPE–TB–TPA (D–π–A), and Py–TB–TPA (D–π–A) CMPs have been designed and synthesized via Suzuki and Sonogashira–Hagihara coupling reaction, respectively. Our investigation of TPA–CMP materials showed that TPA–TPA, Py–TPA, and TPA–TB–TPA CMPs exhibited elevated T_d10 values, measuring 557 °C, 508 °C, and 482 °C, respectively. Additionally, based on the results of thermal gravimetric analysis (TGA) and nitrogen adsorption–desorption measurements, these CMPs displayed specific surface areas (S_BET) of 98, 913, and 459 m² g⁻¹, respectively. Furthermore, in the order presented, the Py–TPA, and Py–TB–TPA CMPs showcase hydrogen evolution rate (HER) values of 3633, and 16 700 μmol g⁻¹ h⁻¹, respectively. As per density functional theory (DFT) calculations, the presence of an alkyne bridge in the Py–TB–TPA CMP can effectively hinder electron–hole recombination, prolong the lifetime of charge carriers, and improve the efficiency of their transfer and separation when compared to a similar CMP (Py–TPA CMP) lacking an alkynyl group. As a result, including an alkynyl (π) bridge in the polymers led to an augmentation in their photocatalytic activity. This work presents various viewpoints regarding the development and architecture of high-performance CMPs incorporating alkynyl groups, showcasing their potential applications in photocatalysis.

Owing to encyclopedic energy crises and ecological concerns, the conversion of solar energy into sustainable value-added fuel products using a reasonable photocatalyst has received a lot of interest. The crucial challenge of the photoreduction of CO₂ into fuel products such as CO and CH₄ is the minor output and poor selectivity. Herein, a novel synthesized schottky-functionalized type-II heterojunction, Ag/CuNb₂O₆/g-C₃N₄ (Ag/CNO/g-CN), is extensively characterized to provide insights regarding its photocatalytic performance in reducing CO₂. More significantly, electron paramagnetic resonance was employed to assist in understanding the inclusion of Schottky-junction and type II heterojunction charge transfer. The CO₂ photoreduction to CO (2.78 μmol g⁻¹h⁻¹) with Ag/CNO/g-CN was 5- and 3-fold higher than single CNO and single g-CN, and the CO₂ photoreduction to CH₄ was 0.15 μmol g⁻¹h⁻¹ under simulated solar irradiation. This enhanced CO₂ photoreduction was attributed to the large surface area and type II heterojunction, which promoted the separation as well as the transformation of photoinduced e⁻/h⁺ pairs and the superior redox ability of charge carriers. The composite's excellent photocatalytic efficiency towards CO₂ was exceptionally enhanced by depositing Ag on CNO/g-CN. This study paves the way for immediate needs to explore the selective conversion of CO₂ into CO and CH₄ via systematic designing and effective schottky-functionalized type-II heterojunction.

The lack of intrinsic active sites for photocatalytic CO₂ reduction reaction (CO₂RR) and fast recombination rate of charge carriers are the main obstacles to achieving high photocatalytic activity. In this work, a novel phosphorus and boron binary-doped graphitic carbon nitride, highly porous material that exhibits powerful photocatalytic CO₂ reduction activity, specifically toward selective CO generation, is disclosed. The coexistence of Lewis-acidic and Lewis-basic sites plays a key role in tuning the electronic structure, promoting charge distribution, extending light-harvesting ability, and promoting dissociation of excitons into active carriers. Porosity and dual dopants create local chemical environments that activate the pyridinic nitrogen atom between the phosphorus and boron atoms on the exposed surface, enabling it to function as an active site for CO₂RR. The P–N–B triad is found to lower the activation barrier for reduction of CO₂ by stabilizing the COOH reaction intermediate and altering the rate-determining step. As a result, CO yield increased to 22.45 µmol g⁻¹ h⁻¹ under visible light irradiation, which is ≈12 times larger than that of pristine graphitic carbon nitride. This study provides insights into the mechanism of charge carrier dynamics and active site determination, contributing to the understanding of the photocatalytic CO₂RR mechanism.

Reduction of CO₂ to value-added hydrocarbons through artificial photosynthesis is one of the way to address the energy crisis and climate change issues. It is known that lowering the activation energy of CO₂ molecules on the photocatalyst surface and key intermediates is crucial in photocatalytic CO₂ reduction. Herein, we present phosphorus-implanted 20-nm SnS₂ continuous thin film with sulfur vacancies (i.e., S_V-SnS₂:P where P substitutes on S sites). The fabrication process involves thermal evaporation, post-sulfurization, and ion implantation. Our gas-phase photocatalytic experiments show an enhanced and selective CO₂ photoreduction to CH₄ with a yield of 0.13 µmol cm⁻² and selectivity of 92 % under solar-light irradiation for 4 h over an optimal ∼4.5 % P and ∼16 % S_V. Experimental observations, conducted through X-ray absorption near edge, in situ near ambient pressure X-ray photoelectron, and in situ Fourier transform infrared spectroscopies, along with first-principle density functional theory calculations. Results reveal that P dopant is significantly affected by nearby S_V via local charge density transfer from P to the nearest Sn and next-nearest S neighbor atoms, consequently, leads to the stabilization of *COOH and *CHO intermediates, where asterisks stand for P as the active site. Our results demonstrate how active site modulation, without using precious co-catalysts, plays a crucial role in intermediate stabilization in a wireless photocatalysis process.