Photothermal catalysis for CO2 conversion

The conversion of carbon dioxide into useful fuels or chemical feedstocks is of great importance for achieving carbon emission peak and carbon neutrality. The harvesting and conversion of solar energy will provide a sustainable and environmentally friendly energy source for human production and living. Very recently, photothermal catalysis has been proved to exhibit great advantages in reducing the reaction temperature, promoting the catalytic activity, and manipulating the reaction pathway in comparison with traditional thermal catalysis. In this review, we firstly introduced the fundamental mechanisms and categories of photothermal catalysis to understand the synergy or the difference between photochemical and thermochemical reaction pathways. Subsequently, the criteria and strategies for photothermal catalyst design are discussed in order to inspire the development of high-efficiency photothermal catalytic route by achieving intense absorption of broadband solar energy spectrum and high conversion capability of solar-to-heat. Recent progress in CO₂ reduction achieved by photothermal catalysis was summarized in terms of production types. In the end, the future challenges and perspectives of photothermal catalytic CO₂ reduction are presented. We hope that this review will not only deepen the understanding of photothermal catalysis, but also inspire the design, preparation and application of high-performance photothermal catalysts, aiming at alleviating non-renewable fossil energy consumption and carbon emissions for early carbon emission peak and carbon neutrality.     

Nanoplasmonic zirconium nitride photocatalyst for direct overall water splitting

The ability of plasmonic nanostructures to efficiently harvest light energy and generate energetic hot carriers makes them promising materials for utilization in photocatalytic water spitting.Apart from the traditional Au and Ag based plasmonic photocatalysts,more recently the noble-metal-free alternative plasmonic materials have attracted ever-increasing interest.Here we report the first use of plasmonic zirconium nitride（ZrN） nanoparticles as a promising photocatalyst for water splitting.Highl...     

Recent advances in 1D nanostructured catalysts for photothermal and photocatalytic reduction of CO2

The development of photocatalysts that can efficiently convert CO₂ into other valuable chemicals via photocatalytic and photothermal processes is critical to the current energy and climate change problems. However, low separation of charge carriers, short light absorption, and low activation of CO₂ molecules in photocatalysis limit the catalysts’ performance. Designing 1D heterostructures containing multiple materials can be a viable solution as their unique properties, such as high surface area, short diffusion paths of charge carriers, and enhanced light absorption properties, can potentially promote the reaction rate and product selectivity. In this review, we summarize the general features of heterostructures involving nanotubes, nanowires, nanorods, and nanobelts. Next, the main synthesis strategies are briefly highlighted, followed by the most important findings concerning their catalytic activity in the photothermal and photocatalytic CO₂ reduction processes. The article concludes with some of the current challenges and potential solutions.     

Plasmonic Cu Nanoparticles for the Low-temperature Photo-driven Water-gas Shift Reaction

The activation of water molecules in thermal catalysis typically requires high temperatures, representing an obstacle to catalyst development for the low-temperature water-gas shift reaction (WGSR). Plasmonic photocatalysis allows activation of water at low temperatures through the generation of light-induced hot electrons. Herein, we report a layered double hydroxide-derived copper catalyst (LD-Cu) with outstanding performance for the low-temperature photo-driven WGSR. LD-Cu offered a lower activation energy for WGSR to H₂ under UV/Vis irradiation (1.4 W cm⁻²) compared to under dark conditions. Detailed experimental studies revealed that highly dispersed Cu nanoparticles created an abundance of hot electrons during light absorption, which promoted *H₂O dissociation and *H combination via a carboxyl pathway, leading to the efficient production of H₂. Results demonstrate the benefits of exploiting plasmonic phenomena in the development of photo-driven low-temperature WGSR catalysts.     

MOF Encapsulated AuPt Bimetallic Nanoparticles for Improved Plasmonic-induced Photothermal Catalysis of CO2 Hydrogenation

Exploring new catalytic strategies for achieving efficient CO₂ hydrogenation under mild conditions is of great significance for environmental remediation. Herein, a composite photocatalyst Zr-based MOF encapsulated plasmonic AuPt alloy nanoparticles (AuPt@UiO-66-NH₂) was successfully constructed for the efficient photothermal catalysis of CO₂ hydrogenation. Under light irradiation at 150 °C, AuPt@UiO-66-NH₂ achieved a CO production rate of 1451 μmol g_metal⁻¹ h⁻¹ with 91 % selectivity, which far exceeded those obtained by Au@Pt@UiO-66-NH₂ with Pt shell on Au (599 μmol g_metal⁻¹ h⁻¹) and Au@UiO-66-NH₂ (218 μmol g_metal⁻¹ h⁻¹). The outstanding performances of AuPt@UiO-66-NH₂ were attributed to the synergetic effect originating from the plasmonic metal Au, doped active metal Pt, and encapsulation structure of UiO-66-NH₂ shell. This work provides a new way for photothermal catalysis of CO₂ and a reference for the design of high-performance plasmonic catalysts.     

Dual-Plasmon Resonance Coupling Promoting Directional Photosynthesis of Nitrate from Air

Photocatalysis, particularly plasmon-mediated photocatalysis, offers a green and sustainable approach for direct nitrogen oxidation into nitrate under ambient conditions. However, the unsatisfactory photocatalytic efficiency caused by the limited localized electromagnetic field enhancement and short hot carrier lifetime of traditional plasmonic catalysts is a stumbling block to the large-scale application of plasmon photocatalytic technology. Herein, we design and demonstrate the dual-plasmonic heterojunction (Bi/Cs_xWO₃) achieves efficient and selective photocatalytic N₂ oxidation. The yield of NO₃⁻ over Bi/Cs_xWO₃ (694.32 μg g⁻¹ h⁻¹) are 2.4 times that over Cs_xWO₃ (292.12 μg g⁻¹ h⁻¹) under full-spectrum irradiation. The surface dual-plasmon resonance coupling effect generates a surge of localized electromagnetic field intensity to boost the formation efficiency and delay the self-thermalization of energetic hot carriers. Ultimately, electrons participate in the formation of ⋅O₂⁻, while holes involve in the generation of ⋅OH and the activation of N₂. The synergistic effect of multiple reactive oxygen species drives the direct photosynthesis of NO₃⁻, which achieves the overall-utilization of photoexcited electrons and holes in photocatalytic reaction. The concept that the dual-plasmon resonance coupling effect facilitates the directional overall-utilization of photoexcited carriers will pave a new way for the rational design of efficient photocatalytic systems.     

Near Infrared Light-to-Heat Conversion for Liquid-Phase Oxidation Reactions by Antimony-Doped Tin Oxide Nanocrystals

Effective utilization of the sunlight for chemical reactions is pivotal for dealing with the growing energy and environmental issues. So far, much effort has been focused on the development of semiconductor photocatalysts responsive to UV and visible light. However, the near infrared and infrared (NIR-IR) light occupying ∼50 % of the solar energy has usually been wasted because of the low photon energy insufficient for the band gap excitation. Antimony doping into SnO₂ (ATO) induces strong absorption due to the conduction band electrons in the NIR region. The absorbed light energy is eventually converted to heat via the interaction between hot electrons and phonons. This Concept highlights the photothermal effect of ATO nanocrystals (NCs) on liquid-phase oxidation reactions through the NIR light-to-heat conversion. Under NIR illumination even at an intensity of ∼0.5 sun, the reaction field temperature on the catalyst surface is raised 20–30 K above the bulk solution temperature, while the latter is maintained near the ambient temperature. In some reactions, this photothermal local heating engenders the enhancement of not only the catalytic activity and selectivity but also the regeneration of catalytically active sites. Further, the photocatalytic activity of semiconductors can be promoted. Finally, the conclusions and possible subjects in the future are summarized.     

Integrated Photochromic-Photothermal Processes for Catalytic Plastic Upcycling

Incorporating high-energy ultraviolet (UV) photons into photothermal catalytic processes may enable photothermal-photochemical synergistic catalysis, which represents a transformative technology for waste plastic recycling. The major challenge is avoiding side reactions and by-products caused by these energetic photons. Here, we break through the limitation of the existing photothermal conversion mechanism and propose a photochromic-photothermal catalytic system based on polyol-ligated TiO₂ nanocrystals. Upon UV or sunlight irradiation, the chemically bonded polyols can rapidly capture holes generated by TiO₂, enabling photogenerated electrons to reduce Ti⁴⁺ to Ti³⁺ and produce oxygen vacancies. The resulting abundant defect energy levels boost sunlight-to-heat conversion efficiency, and simultaneously the oxygen vacancies facilitate polyester glycolysis by activating the nucleophilic addition-elimination process. As a result, compared to commercial TiO₂ (P25), we achieve 6-fold and 12.2-fold performance enhancements under thermal and photothermal conditions, respectively, while maintaining high selectivity to high-valued monomers. This paradigm-shift strategy directs energetic UV photons for activating catalysts and avoids their interaction with reactants, opening the possibility of substantially elevating the efficiency of more solar-driven catalysis.     

Quantifying the Contribution of Hot Electrons in Photothermal Catalysis: A Case Study of Ammonia Synthesis over Carbon-supported Ru Catalyst

Photothermal catalysis is one of the most promising green catalytic technologies, while distinguishing the effects of hot electrons and local heating remains challenging. Herein, we reported that the actual reaction temperature of photothermal ammonia synthesis over carbon-supported Ru catalyst can be measured based on Le Chatelier′s principle, enabling the hot-electron contribution to be quantified. By excluding local heating effects, we established that the activation energy via photothermal catalysis was much lower than that of thermocatalysis (54.9 vs. 126.0 kJ mol⁻¹), stemming from hot-electron injection lowering the energy barriers for both N₂ dissociation and intermediates hydrogenation. Furthermore, hot-electron injection acted to suppress carbon support methanation, giving the catalyst outstanding operational stability over 1000 h. This work provides new insights into the hot-electron effects in ammonia synthesis, guiding the design of high-performance photothermal catalysts.     

Nano-Impact Single-Entity Electrochemistry Enables Plasmon-Enhanced Electrocatalysis**

Plasmon-enhanced electrocatalysis (PEEC), based on a combination of localized surface plasmon resonance excitation and an electrochemical bias applied to a plasmonic material, can result in improved electrical-to-chemical energy conversion compared to conventional electrocatalysis. Here, we demonstrate the advantages of nano-impact single-entity electrochemistry (SEE) for investigating the intrinsic activity of plasmonic catalysts at the single-particle level using glucose electrooxidation and oxygen reduction on gold nanoparticles as model reactions. We show that in conventional ensemble measurements, plasmonic effects have minimal impact on photocurrents. We suggest that this is due to the continuous equilibration of the Fermi level (E_F) of the deposited gold nanoparticles with the E_F of the working electrode, leading to fast neutralization of hot carriers by the measuring circuit. The photocurrents detected in the ensemble measurements are primarily caused by photo-induced heating of the supporting electrode material. In SEE, the E_F of suspended gold nanoparticles is unaffected by the working electrode potential. As a result, plasmonic effects are the dominant source of photocurrents under SEE experimental conditions.     

光热协同效应在催化反应中的应用研究进展

近几年,随着催化研究的逐渐深入,将两种或多种手段耦合,能够明显地改善催化性能,其中光热协同催化是当前新型催化技术研究的焦点.我们介绍了光热协同催化在能源合成领域的应用,尤其在光热催化CO_2转化、污染物降解、制氢和费托合成等反应.研究结果表明,两者的有效结合可以超越单独热催化或光催化所能达到的效果,在某些反应中能够明显提高产物的收率,改善目标产物的选择性以及降低反应的温度.最后还展望了光热协同催化发展的前景,以及目前仍然面临反应机理尚不明确和合适催化剂的筛选等问题.     

基于单原子催化剂的光热催化转化：原理和应用

在以碳中和为目标的全球共识下,太阳能作为一种取之不竭用之不尽的绿色环保能源被认为是替代传统化石燃料最有潜力的方式。在各种太阳能转换技术中,光热催化不仅可以最大化利用太阳能,在光场和热场双重驱动力作用下,还可以显著提升化学反应速率,引起广泛的研究兴趣。以孤立的单个原子均匀分散在载体上形成的单原子催化剂具有100%原子利用率、优异的催化活性、热稳定性等优势。因此,将单原子催化剂应用于光热催化开始受到越来越多的关注。本综述介绍了光催化、热催化和光热催化的基本原理和特征,同时列举一些典型的例子。随后以不同载体作为分类标准,总结了单原子光热催化应用的前沿研究进展。最后,提出了该催化体系所面临的挑战和未来的发展方向。本文旨在全面了解单原子催化剂在太阳能驱动光热催化领域的研究现状并为未来发展提供可行的建议。     

Photothermal Conversion of CO2 into CH4 with H2 over Group VIII Nanocatalysts: An Alternative Approach for Solar Fuel Production

The photothermal conversion of CO₂ provides a straightforward and effective method for the highly efficient production of solar fuels with high solar‐light utilization efficiency. This is due to several crucial features of the Group VIII nanocatalysts, including effective energy utilization over the whole range of the solar spectrum, excellent photothermal performance, and unique activation abilities. Photothermal CO₂ reaction rates (mol h^?1 g^?1) that are several orders of magnitude larger than those obtained with photocatalytic methods (μmol h^?1 g^?1) were thus achieved. It is proposed that the overall water‐based CO₂ conversion process can be achieved by combining light‐driven H₂ production from water and photothermal CO₂ conversion with H₂. More generally, this work suggests that traditional catalysts that are characterized by intense photoabsorption will find new applications in photo‐induced green‐chemistry processes.     

Basic ionic liquids promoted chemical transformation of CO<Subscript>2</Subscript> to organic carbonates

Ionic liquids (ILs), especially basic ILs with unique physicochemical properties, have wide application in catalysis. Using basic ILs as catalysts for the conversion of cheap, abundant, nontoxic, and renewable CO₂ into value-added organic carbonates is highly significant in view of environmental and economic issues. This review aims at giving a detailed overview on the recent advances on basic ILs promoted chemical transformation of CO₂ to cyclic and linear carbonates. The structures of various basic ILs, as well as the basic ILs promoted reactions for the transformation of CO₂ to organic carbonates are discussed in detail, including the reaction conditions, the yields of target products, the catalytic activities of basic ILs and the reaction mechanism.     

慢光子效应在太阳能转换燃料中的应用（英文）

随着全球性能源短缺和环境恶化问题的日益突出,能源和环境问题已成为目前人类面临和亟待解决的重大难题,研究新的替代能源和清洁环境技术备受关注.世界各国的科研工作者都在积极探索和寻找有效的对策,其中通过光催化分解水和还原CO_2将太阳能转化为有价值的氢气和碳氢燃料可有效缓解人类对可再生能源和清洁能源的需求.然而,现有催化剂的转换效率还达不到商业化的要求,主要原因是太阳光的利用率低和光生电荷的复合率高.将催化剂构造成三维有序孔状的光子晶体结构,可有效提高催化剂对光的利用率.光子晶体是一种特殊的周期性介电物质有序排列而成的微结构材料,它对光有着特殊的调控作用,可以通过光反射、光散射和慢光子效应来调控光在材料介质结构中的传播和光与介质的相互作用.三维反蛋白石结构的光子晶体不仅有光子晶体的特征还具有本身特有的结构效应,主要体现在以下两个方面:(1)光子晶体结构:光子晶体具有内部相互连接的三维框架结构和相互连通的球形孔道,三维框架结构提供大的比表面积,而有序的球形孔道有利于反应物分子的动态扩散;(2)光子晶体效应:当光波长落在光子禁带范围内,此波长的光将会被反射而不能在材料内传播;当光子晶体材料内有缺陷时可以发生多重散射,增加光的利用率;当光波长落在光子禁带红边的时候,这部分的光将会"慢下来"并且作用光子晶体的高介电物质部分;当光波长落在光子禁带蓝边的时候,这部分光也会"慢下来"并且作用于光子晶体的低介电物质部分.通过调控光子禁带的位置,可以得到不同波长的慢光子和调控作用于不同的材料物质上,增强入射光的利用率和光与材料的相互作用.基于光子晶体半导体材料既有电子能带又有光子能带的特点,利用光的反射、散射和慢光子效应来调控光在光子晶体中的传播,能显著增强光与催化剂的相互作用.尤其是光子禁带附近产生的慢光子效应对光有着特殊的调控作用,可以减慢一些特定频率的入射光在催化剂中的传输,促进催化剂对光的吸收.同时,慢光子效应还能促进光生电子-空穴对的分离,提高光解水产氢和光化学还原CO_2的活性.本文总结了光子晶体的慢光子效应促进光催化产H_2和CO_2还原的最新发展,并研究了慢光子效应在太阳能转换为燃料中的作用.基于慢光子效应对光的特殊调控作用,构造具有光子晶体结构的催化剂对促进太阳光的吸收和提高太阳能转换为燃料的效率具有重要的意义.     

Prolonged Hot Electron Dynamics in Plasmonic‐Metal/Semiconductor Heterostructures with Implications for Solar Photocatalysis

Ideal solar‐to‐fuel photocatalysts must effectively harvest sunlight to generate significant quantities of long‐lived charge carriers necessary for chemical reactions. Here we demonstrate the merits of augmenting traditional photoelectrochemical cells with plasmonic nanoparticles to satisfy these daunting photocatalytic requirements. Electrochemical techniques were employed to elucidate the mechanics of plasmon‐mediated electron transfer within Au/TiO₂ heterostructures under visible‐light (λ>515 nm) irradiation in solution. Significantly, we discovered that these transferred electrons displayed excited‐state lifetimes two orders of magnitude longer than those of electrons photogenerated directly within TiO₂ via UV excitation. These long‐lived electrons further enable visible‐light‐driven H₂ evolution from water, heralding a new photocatalytic paradigm for solar energy conversion.     

An efficient Ag/MIL-100(Fe) catalyst for photothermal conversion of CO2 at ambient temperature

The conversion of CO₂ under mild condition is of great importance because these reactions involving CO₂ can not only produce value-added chemicals from abundant and inexpensive CO₂ feedstock but also close the carbon cycle. However, the chemical inertness of CO₂ requires the development of high-performance catalysts. Herein, Ag nanoparticles/MIL-100(Fe) composites were synthesized by simple impregnation-reduction method and employed as catalysts for the photothermal carboxylation of terminal alkynes with CO₂. MIL-100(Fe) could stabilize Ag nanoparticles and prevent them from aggregation during catalytic process. Taking the advantages of photothermal effects and catalytic activities of both Ag nanoparticles and MIL-100(Fe), various aromatic alkynes could be converted to corresponding carboxylic acid products (86%–92% yields) with 1 atm CO₂ at room temperature under visible light irradiation when using Ag nanoparticles/MIL-100(Fe) as photothermal catalysts. The catalysts also showed good recyclability with almost no loss of catalytic activity for three consecutive runs. More importantly, the catalytic performance of Ag nanoparticles/MIL-100(Fe) under visible light irradiation at room temperature was comparable to that upon heating, showing that the light source could replace conventional heating method to drive the reaction. This work provided a promising strategy of utilizing solar energy for achieving efficient CO₂ conversion to value-added chemicals under mild condition.     

Molecular-level Manipulation of Interface Charge Transfer on Plasmonic Metal/MOF Heterostructures

Plasmon-excited hot carriers have drawn great attention for driving various chemical reactions, but the short lifetimes of hot carriers seriously restrict the performance of plasmonic photocatalysis. Constructing plasmonic metal/metal-organic framework (MOF) heterostructures has been proved as an effective strategy to extend the lifetimes of hot carriers. Due to the high molecular tunability of MOFs, the MOF substrate in plasmonic metal/MOF heterostructures is able to capture hot electrons on the conduction band of MOF and hot holes on its valence band, and thus offers an ideal platform to separately study the detailed mechanism of hot electron and hole transfer processes. This review focuses on a molecular-level understanding of both hot-electron and hot-hole transfer at plasmonic metal/MOF interfaces. The enhanced stability and photocatalytic performance by introducing MOF substrates are discussed for plasmonic metal/MOF heterostructures. Additionally, typical characterization technologies are also proposed as powerful tools for tracking hot carrier transfer process.     

Disorder Engineering in Monolayer Nanosheets Enabling Photothermic Catalysis for Full Solar Spectrum (250–2500 nm) Harvesting

A persistent challenge in classical photocatalyst systems with extended light absorption is the unavoidable trade‐off between maximizing light harvesting and sustaining high photoredox capability. Alternatively, cooperative energy conversion through photothermic activation and photocatalytic redox is a promising yet unmet scientific proposition that critically demands a spectrum‐tailored catalyst system. Here, we construct a solar thermal‐promoted photocatalyst, an ultrathin “biphasic” ordered–disordered D‐HNb₃O₈ junction, which performs two disparate spectral selective functions of photoexcitation by ordered structure and thermal activated conversion via disordered lattice for combinatorial photothermal mediated catalysis. This in situ synthetically immobilized lattice distortion, constrained to a single‐entity monolayer structure not only circumvents interfacial incompatibility but also triggers near‐field temperature rise at the catalyst–reactant complexes’ proximity to promote photoreaction. Ultimately, a generic full solar conversion improvement for H₂ fuel production, organic transformation and water purification is realized.     

Suppressive Strong Metal-Support Interactions on Ruthenium/TiO2 Promote Light-Driven Photothermal CO2 Reduction with Methane

Strong metal-support interactions (SMSI) have gained great attention in the heterogeneous catalysis field, but its negative role in regulating light-induced electron transfer is rarely explored. Herein, we describe how SMSI significantly restrains the activity of Ru/TiO₂ in light-driven CO₂ reduction by CH₄ due to the photo-induced transfer of electrons from TiO₂ to Ru. In contrast, on suppression of SMSI Ru/TiO₂−H₂ achieves a 46-fold CO₂ conversion rate compared to Ru/TiO₂. For Ru/TiO₂−H₂, a considerable number of photo-excited hot electrons from Ru nanoparticles (NPs) migrate to oxygen vacancies (OVs) and facilitate CO₂ activation under illumination, simultaneously rendering Ru^δ+ electron deficient and better able to accelerate CH₄ decomposition. Consequently, photothermal catalysis over Ru/TiO₂−H₂ lowers the activation energy and overcomes the limitations of a purely thermal system. This work offers a novel strategy for designing efficient photothermal catalysts by regulating two-phase interactions.