Photothermal Catalysis Research Articles

Highly Efficient Photothermal Reduction of CO2 on Pd2Cu Dispersed TiO2 Photocatalyst and Operando DRIFT Spectroscopic Analysis of Reactive Intermediates.

The photocatalytic conversion of CO2 to fuels using solar energy presents meaningful potential in the mitigation of global warming, solar energy conversion, and fuel production. Photothermal catalysis is one promising approach to convert chemically inert CO2 into value-added chemicals. Herein, we report the selective hydrogenation of CO2 to ethanol by Pd2Cu alloy dispersed TiO2 (P25) photocatalyst. Under UV-Vis irradiation, the Pd2Cu/P25 showed an efficient CO2 reduction photothermally at 150 °C with an ethanol production rate of 4.1 mmol g−1 h−1. Operando diffuse reflectance infrared Fourier transform (DRIFT) absorption studies were used to trace the reactive intermediates involved in CO2 hydrogenation in detail. Overall, the Cu provides the active sites for CO2 adsorption and Pd involves the oxidation of H2 molecule generated from P25 and C–C bond formation.

Greener and higher conversion of esterification via interfacial photothermal catalysis

Greener and higher conversion of esterification via interfacial photothermal catalysis

Scalable combustion synthesis of copper-based perovskite catalysts for CO2 reduction to methanol: Reaction structure-activity relationships, kinetics, and stability

The selectivity of the CO2 hydrogenation can be tuned easily by altering the chemical Cu oxidation state, the correlated synergistic effect between copper, alkaline metal elements and support, and operation. In this mechanistic work, several perovskite-containing Cu/Sr/Ti materials were prepared, using one-step solution combustion method, by varying characteristic system parameters, including fuel selection relationship, maximal reference Cu loading, the type of deposition and the size of nanoparticles, Sr/Ti ratio, physical calcination temperature and the series of reactions. The activity under application was measured at relevant functional methanol synthesis conditions (200–280 °C, 20–50 bar and 8,000–24,000 h−1), validated to be stable, and connected with component physicochemical properties, identified applying X-ray powder diffraction (XRD), benchmarking and Rietveld refinement, N2 physisorption, the scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy- (EDS), the temperature-programmed reduction of H2 (H2 TPR), N2O pulsed surface oxidation (N2O PSO) and the temperature-programmed desorption of CO2 (CO2 TPD) interactions. Aqueous citric acid was assessed as the most suitable energy source; the optimal experimental heating was at 650 °C, balancing remaining nitrate ions, thermal sintering, and active Cu sites, while adsorption surface area was high. Additionally, a long-term stability determination test of the best-manufactured product (Cu5Sr3Ti2OX) was performed, deactivation was analysed, and derived kinetic model was constructed, which adequately described intrinsic catalytic behaviour over a broad operational range investigated. Graaf kinetics were assumed to be suitable for commercial Cu/ZnO/Al2O3, integrating the sorption, rates, and equilibrium into macro-kinetics, removing resistances of transport phenomena. Semiconductors as substrates facilitate the extrapolation of solar-driven photo-thermal catalysis.

ZIF-L-derived ZnO/N-doped carbon with multiple active sites for efficient catalytic CO2 cycloaddition

Integration of Lewis acid and base sites and oxygen surface groups in one catalyst is favorable to promote CO2 cycloaddition reaction. Here, Zn-ZIF-L was used as starting material to design one kind of catalyst with multiple active sites via pyrolysis and oxidization treatment. The well-dispersed ZnO nanoparticles and pyridinic nitrogen in nitrogen-doped carbon serve as Lewis acid and base sites to activate epoxide and CO2 while oxygen surface groups help promote the ring-opening reaction of epoxides. Results show that Zn-ZIF-L derived catalyst displays high catalytic activities for CO2 cycloaddition (6 h, 83% of yield) under mild conditions (70 °C and 0.1 MPa CO2) and outperforms ZIF-8 derived catalyst. Moreover, the obtained catalyst also achieves a satisfactory photothermal catalysis of cycloaddition reaction under light irradiation (120 mW/cm2), which makes our sample a promising catalyst for CO2 conversion.

Development of defective molybdenum oxides for photocatalysis, thermal catalysis, and photothermal catalysis.

The localized surface plasmon resonance (LSPR) of noble metals has been investigated for decades for applications in various catalysis reactions and optical research studies, but its development has been hampered by inefficient light absorption and high costs. In comparison, the creation of less expensive semiconductors (metal oxides) with strong plasmonic absorption is an appealing option, particularly defective molybdenum oxide (HxMoO3-y) has received considerable attention and investigation as a promising plasmonic material for a variety of catalytic reactions (photocatalysis, thermocatalysis, photothermal catalysis, etc.).The LSPR effect of HxMoO3-y can be tuned throughout a broad spectrum range from visible to near-infrared (NIR) by altering the doping amount by electrochemical control, chemical reduction, or photochemical control. Notably, defects (oxygen vacancies) in HxMoO3-y arise in conjunction with the LSPR effect, resulting in the formation of unique and useful active sites in a range of catalytic processes. In this review, we explore the formation mechanism of HxMoO3-y with plasmonic features and discuss its applications in photocatalysis, thermocatalysis, and photothermal catalysis.

Photothermal Catalysis Without Solvent for Fixing Co2 to Cyclic Carbonate

Photothermal Catalysis Without Solvent for Fixing Co2 to Cyclic Carbonate

Photothermal synergy for efficient dry reforming of CH4 by an Ag/AgBr/CsPbBr3 composite

Dry reforming of CH4 by photothermal catalysis is considered to be a promising approach to produce syngas.

Nanostructured Photothermal Materials for Environmental and Catalytic Applications.

Solar energy is a green and sustainable clean energy source. Its rational use can alleviate the energy crisis and environmental pollution. Directly converting solar energy into heat energy is the most efficient method among all solar conversion strategies. Recently, various environmental and energy applications based on nanostructured photothermal materials stimulated the re-examination of the interfacial solar energy conversion process. The design of photothermal nanomaterials is demonstrated to be critical to promote the solar-to-heat energy conversion and the following physical and chemical processes. This review introduces the latest photothermal nanomaterials and their nanostructure modulation strategies for environmental (seawater evaporation) and catalytic (C1 conversion) applications. We present the research progress of photothermal seawater evaporation based on two-dimensional and three-dimensional porous materials. Then, we describe the progress of photothermal catalysis based on layered double hydroxide derived nanostructures, hydroxylated indium oxide nanostructures, and metal plasmonic nanostructures. Finally, we present our insights concerning the future development of this field.

Cooperative catalysis coupling photo-/photothermal effect to drive Sabatier reaction with unprecedented conversion and selectivity

•We designed a catalyst coupling photo-/photothermal effect for Sabatier reaction •The 0.35%[email protected]2V2O7 catalyst achieved a record CH4 production rate •The conversion and selectivity approached the thermodynamic equilibrium limit The development of highly efficient catalysts to drive the Sabatier reactions under mild conditions remains a great challenge. Here, we report a 0.35%[email protected]2V2O7 catalyst exhibited an unprecedented solar-driven CO2 methanation rate of 114.9 mmol gcat−1h−1 (32.8 mol gRu−1 h−1 as normalized to the mass of the Ru catalyst), which was approximately 40 and 460 times larger than the rates obtained over the bare Ni2V2O7 and [email protected]2 catalysts, respectively. Moreover, the 0.35%[email protected]2V2O7 catalyst exhibited 93.5% CO2 conversion efficiency and 99% selectivity for CH4 production, approaching the thermodynamic equilibrium limit of thermocatalytic CO2 methanation. Further investigations revealed a cooperative mechanism coupling photocatalysis and photothermal catalysis between the Ru and Ni2V2O7. When illuminated, Ru clusters acted as a “nanoheater” and raised the local temperature to activate H2 and desorb H2O molecules. The spilled H adatoms reacted with adsorbed CO2 on the surface of O-vacancy-rich Ni2V2O7 to achieve cooperative catalysis for CO2 methanation. The development of highly efficient catalysts to drive the Sabatier reactions under mild conditions remains a great challenge. Here, we report a 0.35%[email protected]2V2O7 catalyst exhibited an unprecedented solar-driven CO2 methanation rate of 114.9 mmol gcat−1h−1 (32.8 mol gRu−1 h−1 as normalized to the mass of the Ru catalyst), which was approximately 40 and 460 times larger than the rates obtained over the bare Ni2V2O7 and [email protected]2 catalysts, respectively. Moreover, the 0.35%[email protected]2V2O7 catalyst exhibited 93.5% CO2 conversion efficiency and 99% selectivity for CH4 production, approaching the thermodynamic equilibrium limit of thermocatalytic CO2 methanation. Further investigations revealed a cooperative mechanism coupling photocatalysis and photothermal catalysis between the Ru and Ni2V2O7. When illuminated, Ru clusters acted as a “nanoheater” and raised the local temperature to activate H2 and desorb H2O molecules. The spilled H adatoms reacted with adsorbed CO2 on the surface of O-vacancy-rich Ni2V2O7 to achieve cooperative catalysis for CO2 methanation.

Light-promoted activation of oxygen and carbon monoxide for low-temperature catalytic oxidation

Molecular oxygen (O 2 ) activation is a critical step in the low-temperature catalytic oxidation of carbon monoxide (CO). Photocatalysis is a facile way to activate O 2 to superoxide radicals under mild conditions. Photothermal catalysis, which integrates the photocatalysis of semiconductors and the thermocatalysis of noble metals, has arisen as an appealing strategy to achieve low-temperature catalytic oxidation. Here, we report that Pd/PdO/CeO 2 shows that the temperature of 90% CO conversion dropped by 30°C–50°C under irradiation. The apparent activation energy reduces from 64.6 kJ ⋅ mol −1 to 44.6 kJ ⋅ mol −1 . Pd/PdO/TiO 2 and Pd/PdO/Al 2 O 3 are prepared and compared to understand the underlying mechanism. The results reveal that photocatalysis is vital in lowering the apparent activation energy besides the photothermal effect. The photo-generated electrons promote O 2 activation to generate the superoxide anion. The hole can activate the adsorbed CO on the PdO. These active species are beneficial for lowering the CO oxidation temperature. • Pd/PdO/CeO 2 nanowires deposited and annealed in the reaction gas environment • Conversion temperature drops 30°C–50°C under full-spectrum light irradiation • Photocatalytic oxidation provides significant contribution in addition to photothermal effect Here, Dong et al. show photo-assisted thermal catalytic oxidation of CO based on Pd/PdO/CeO 2 . The 90% conversion temperature can be effectively reduced by photocatalytic, Pd plasmonic, and photothermal effects. Photogenerated electrons and holes promote the activation of molecular O 2 and CO to lower the activation energy.

A new strategy towards spectral selectivity: Selective leaching alloy to achieve selective plasmonic solar absorption and infrared suppression

Cost-effective and spectrally selective solar absorbers that possess high solar absorptance, low thermal emittance, and superior thermal stability are essential for photothermal conversion applications, e.g., industrial heating, solar desalination, photothermal catalysis, and concentrating solar power systems. Here, a new strategy using a selective leaching reaction is demonstrated for transfiguring the broad-spectrum and highly reflective aluminum alloys into plasmonic-nanostructure selective solar absorbers (PNSSAs). Enabled by surface plasmon resonance, this strategy via assembling copper nanostructured thin film on an alloy mirror yields tunable manipulation of the spectral selectivity, high and omnidirectional solar absorptance (0.94 from 0 to 60°), low thermal emittance (0.03 at 100 °C), and excellent thermomechanical stability. Featured with merits of competitive performance of spectral selectivity, the feasibility of solution-processed fabrication, and cost-effectiveness of raw materials and chemicals, selective-leaching-alloy to achieve PNSSAs is a promising and universal approach for achieving high photothermal efficiency (85%) of solar thermal energy harvesting. The compatibility of this strategy with other metal alloys, such as steel and superalloys, extends its applications to fabricating mid- and high-temperature selective solar absorbers.

Engineering a Versatile Spectrally Selective Absorber for Moderate‐ and Low‐Temperature Application with Gradient High‐Entropy Nitride Nanofilms

Spectrally selective absorber with superior thermal stability and optical properties is crucial for photothermal conversion applications, including evaporation, anti‐icing, medical sterilization, photothermal catalysis, and solar‐thermal power. Efforts are being made to develop entropy‐stabilized high‐entropy ceramics as high‐performance functional materials, which promise a wide range of potential applications in the fields of energy storage and conversion owing to their diverse compositions and outstanding physical and chemical properties. Herein, an entropy‐stabilized strategy is used to boost the performance of spectrally selective absorbers by carefully choosing a high‐entropy alloy (TiVCrAlZr) target with a reasonable element design, which exhibits a good solar absorptance (α = 96.1%) and low thermal emittance (ϵ = 7.8%). Long‐term thermal stability investigation demonstrates that the entropy‐stabilized absorber could endure at 400 °C for 168 h. Under the irradiation of simulated sunlight, the surface temperature of the absorber can reach up to 105 °C, which is essential for middle‐ and low‐temperature applications. Overall, this work provides significant insights into the spectral selectivity of high‐entropy alloy nitrides and offers a new strategy for designing and developing moderate and low solar selective absorbing coatings via a high‐entropy strategy.

Recent Progress on Photothermal Heterogeneous Catalysts for CO2 Conversion Reactions

Converting the greenhouse gas carbon dioxide into important chemical fuels is promising to alleviate the global warming problem. Photocatalytic CO2 reduction is beneficial for energy storage and environmental protection; however, it suffers from low efficiency. Recently, photothermal catalysis, which merits the advantages of both photocatalysis and traditional thermally driven catalysis, has been extensively studied and proven promising. Herein, the scope of catalyst type within heterogeneous catalysts is discussed, the latest progress of photothermal heterogeneous catalysts designed for CO2 conversion reactions is described, including the reduction of CO2 by H2O, CO2 hydrogenation to CO, CH4, CH3OH, or C2+, CO2 reforming of CH4 (CRM), CO2 cycloaddition reaction, etc. the preparation principles of photothermal catalysts are summarized, the challenges on the design and development of highly efficient photothermal catalysts are pointed out, and the future research directions are prospected.

The Photophysics and Photochemistry of Melanin- Like Nanomaterials Depend on Morphology and Structure.

Melanin‐like nanomaterials have found application in a large variety of high economic and social impact fields as medicine, energy conversion and storage, photothermal catalysis and environmental remediation. These materials have been used mostly for their optical and electronic properties, but also for their high biocompatibility and simplicity and versatility of preparation. Beside this, their chemistry is complex and it yields structures with different molecular weight and composition ranging from oligomers, to polymers as well as nanoparticles (NP). The comprehension of the correlation of the different compositions and morphologies to the optical properties of melanin is still incomplete and challenging, even if it is fundamental also from a technological point of view. In this minireview we focus on scientific papers, mostly recent ones, that indeed examine the link between composition and structural feature and photophysical and photochemical properties proposing this approach as a general one for future research.

Photothermal steam reforming: A novel method for tar elimination in biomass gasification

Tar elimination is the bottleneck which hinders the industrial application of gasification due to the risks of corrosion and blockage in downstream components. Tar production decreases the energy efficiency of gasification systems. The steam reforming is attractive for tar treatment, but the high reaction temperature limits its applications. Photothermal catalysis has the potential to decompose organic pollutants, and it is expected to improve tar removal and reduce the reaction temperature. So, the photothermal steam reforming of toluene was performed to evaluate the toluene conversion. The effects of the toluene concentration, the temperature, the steam to carbon ratio, and the ultraviolet light intensity were investigated. The results showed that, compared with the thermal steam reforming, the photothermal steam reforming could significantly improve the conversion of toluene and promote the formation of gaseous products, especially H2. At 600 °C, the conversion of toluene in the photothermal steam reforming was 90.1%, which was 16.3% higher than that in the thermal steam reforming. Moreover, the mechanisms of the photothermal steam reforming were revealed. The introduction of the ultraviolet irradiation could strongly promote the toluene decomposition and alter the reaction pathways. The carbon deposition and agglomeration of the catalyst were inhibited in photothermal steam reforming. Meanwhile, the toluene removal performance and the energy consumption were compared in photothermal and thermal steam reforming. The potential applications of photothermal catalytic tar removal were also described. These findings proposed a novel approach for low-cost but high-efficiency biomass tar removal, thus promoting the clean utilization of biomass energy.

Enhanced photothermal catalytic performance of dry reforming of methane over Ni/mesoporous TiO2 composite catalyst

Developing new highly efficient catalytic technique is critical for solar photo -thermal -chemical conversion. Among kinds of techniques, photothermal catalysis attracts an increasing attention. In this paper, a Ni/mesoporous TiO2 photothermal catalyst was prepared and applied for methane dry reforming reaction under high temperature environment. Catalytic activities of the prepared catalyst were investigated in a homemade fixed bed photothermal reactor under different temperatures and lighting conditions. And mechanism of photothermal synergistic effect was characterized by using scanning electron microscope (SEM), high resolution transmission electron microscope (HR-TEM), BET, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–Vis-Nir spectrophotometer and Photoluminescence spectra. The results shown that (1) Catalytic activity of the prepared photothermal catalyst in present work performs better than the public reported catalysts in literatures. (2) Comparisons of light and dark experiments of different catalysts proved that the synergistic effect of photothermal catalysis could significantly improve the formation rates of products, and increase the conversions of reactants. The reason is attributed to the formation of Ni-TiO2 heterogeneous structure, which can broaden the optical response range of incident light, as well as enhance the separation of excited e−/h+ pairs in the semiconductor TiO2. (3) Increasing lighting intensity could enhance the formation rates of CO/H2 correspondingly. (4) Compared to catalytic performances of the catalyst under ultraviolet and visible-near-infrared conditions, full spectrum incident light could improve the formation rates of products under the cooperative effect of different spectrum. The testing results indicate that utilizing photothermal synergistic effects to realize the process intensification is beneficial and instructive for the future solar photo -thermal -chemical conversion.

A State-of-the-art review on action mechanism of photothermal catalytic reduction of CO2 in full solar spectrum

The utilization of sunlight and the catalytic effect of the photothermal catalytic reduction of CO2 in the full solar spectrum are improved based on photocatalysis, providing new ideas for mitigating the greenhouse effect and energy crisis. The photothermal catalysis in the full solar spectrum has great development potential. In this paper, by thoroughly discussing the mechanism of light and heat respectively, the photothermal synergy in photothermal catalysis can be explained, the difficulty in exploring the photothermal synergy are solved. This review not only comprehensively and deeply explores the action mechanism of light and heat, but also focuses on the reaction mechanism of photothermal catalytic reduction of CO2, the yield and selectivity of photothermal catalysts. Increasing the surface temperature of the catalyst by photothermal effect, exciting carriers, and high-energy hot electrons, realizing photoactivation, changing the adsorption site and adsorption energy, and reducing the activation energy barrier and reaction temperature are manifested as the action mechanism of light. Increasing the rate of diffusion, adsorption, charge transfer and reaction, providing the energy required to cross the activation energy barrier, and activating thermal active sites are manifested as the action mechanism of heat. Oxygen vacancies are conducive to adsorption, thermal activation and cracking of reactive molecules.

Plasmonic Heating-Promoted Photothermal Synthesis of α-Cyanoacrylonitriles Over Au/h-BN Catalysts.

Plasmonic nanoparticle-involved materials play an essential role in the field of photothermal conversion. Herein, we report the application of photothermal heterogeneous catalysts consisting of gold nanoparticles decorated on defect-rich h-BN sheets (Au/h-BN) for the photocatalytic synthesis of α-cyanoacrylonitriles under mild conditions. It has been demonstrated the–NH2 groups present in the defect-rich h-BN act as the catalytically active sites, while plasmonic heating from the gold nanoparticles can drive the reaction by providing local heat. Au/h-BN catalyst can work for a broad substrate scope in the synthesis of α-cyanoacrylonitriles, and a plausible –NH2 group-involved reaction mechanism has been proposed. This work may open up new avenues in photothermal catalysis by combining plasmonic materials and catalytic sites in one system.

The photothermal effect enhance visible light-driven hydrogen evolution using urchin-like hollow RuO2/TiO2/Pt/C nanomaterial

The photothermal catalysis has attracted much attention as a new catalytic method. Utilization of self-generated heat instead of external heating source is an ideal approach for improving the performance of catalysts. Herein, a novel urchin-like hollow TiO2 photothermal nano-catalyst with spatially separated Pt and RuO2 dual cocatalysts combine with carbon layer (denoted as RuO2/TiO2/Pt/C) is reported for catalytic hydrogen evolution under visible light irradiation. The photothermal catalytic performance of the as-prepared catalysts was evaluated in relation to structural characterizations and the thermal effect of the carbon layer. The sandwich nanostructure of carbon layer, Pt NPs and TiO2 layer effectively support and protect Pt NPs from agglomeration and deactivation of Pt active sites. The hot electrons generated from carbon layer can participate in the photocatalytic reaction. Furthermore, the enhanced visible light absorption performance of TiO2 is explained by narrowing the band gap due to a small amount of doping carbon and reducing the penetration-loss of light via constructing the hollow structure. As a result, the synergy between the spatially separated Pt/RuO2 NPs and the thermal effect with carbon layer greatly improve the catalytic performance of the TiO2-based catalyst for hydrogen production under visible light irradiation.

Energy-efficient photothermal catalysis of rubber seed oil for the preparation of biofuel compounds

Fuel components were prepared in this study using rubber seed oil via photothermal catalysis under energy-saving conditions. Modified TiO2 was employed as the catalyst in the catalytic reactions. X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), X-ray fluorescence (XRF), hydrogen temperature-programmed desorbtion (H2-TPD), CO pulse chemisorption analysis, and UV–vis spectroscopy were employed to examine the microstructure and chemical properties of the modified catalysts. The loading of the catalysts with different active metals considerably reduced the bandgap, leading to enhancements in the absorption of visible light. Temperature, H2 pressure, and reaction time were optimised for the photothermal catalytic reaction via the single factor test. The Pt/TiO2 catalyst realised the highest conversion and selectivity among the tested samples at 120 °C and a H2 pressure of 0.4 MPa for 12 h. Additionally, photo-decarboxylation was confirmed via probing with oleic acid to be the predominant process in the catalytic reaction. This research provides an energy-saving strategy for the preparation of biofuels.