Photothermal Reactions Research Articles

High‐Efficiency and Low‐Intensity Threshold Femtosecond Laser Direct Writing of Precise Metallic Micropatterns on Transparent Substrate

AbstractLaser direct writing (LDW) is a promising approach for fabricating metallic micropatterns on transparent substrates for transparent electronic circuits that satisfy both electronic and optical criteria. However, high efficiency and precision patterning remain a challenge for both photochemical and photothermal LDW. Herein, a novel method is proposed with a femtosecond laser to achieve a highly‐efficient photothermal process via single‐photon absorption by photosensitive particles (SPA‐FsLDW). The dispersive photosensitive particles act as numerous heating sources, enabling simultaneous multiple‐location photothermal reactions and highly‐efficient metallization due to heat‐induced metal ion reduction. The new approach effectively exploits the excellent heat‐input regulation with the ultrashort pulse of the femtosecond laser to achieve great temperature controllability and precision. It is shown that, with a deposition rate of ≈107 µm3 s−1 and electrical resistivity of ≈10−7 Ω m, SPA‐FsLDW improves efficiency and electrical resistivity by at least one order of magnitude compared to previously reported FsLDW. A self‐powered sensor is fabricated using SPA‐FsLDW, demonstrating its practical applicability.

Promoted Photothermal Catalytic CO Hydrogenation by Using TiC-Supported Co-Fe5 C2 Catalysts.

Photothermal catalytic CO hydrogenation offers the potential to synthesize light hydrocarbons by using solar energy. However, the selectivity and activity of the reaction are still far below those achieved in conventional thermal catalytic processes. Herein, we report that the Co-modified Fe5 C2 on TiC catalyst promotes photothermal catalytic CO hydrogenation with a 59 % C2+ selectivity in the produced hydrocarbons and a 30 % single-pass CO conversion at a high gas hourly space-time velocity of 12 000 mL g-1 h-1 . Using in-situ-irradiated XPS, we show that light-induced hot electron injection from TiC to Fe5 C2 modulates the chemical state of Fe, thereby increasing the CO-to-C2+ conversion. This work suggests that it is possible for plasmon-mediated surface chemistry to enhance the activity and selectivity of photothermal catalytic reactions.

Tumor Microenvironment-Adaptive Nanoplatform Synergistically Enhances Cascaded Chemodynamic Therapy.

Chemodynamic therapy (CDT), a noninvasive strategy, has emerged as a promising alternative to conventional chemotherapy for treating tumors. However, its therapeutic effect is limited by the amount of H2O2, pH value, the hypoxic environment of tumors, and it has suboptimal tumor-targeting ability. In this study, tumor cell membrane-camouflaged mesoporous Fe3O4 nanoparticles loaded with perfluoropentane (PFP) and glucose oxidase (GOx) are used as a tumor microenvironment-adaptive nanoplatform (M-mFeP@O2-G), which synergistically enhances the antitumor effect of CDT. Mesoporous Fe3O4 nanoparticles are selected as inducers for photothermal and Fenton reactions and as nanocarriers. GOx depletes glucose within tumor cells for starving the cells, while producing H2O2 for subsequent ·OH generation. Moreover, PFP, which can carry O2, relieves hypoxia in tumor cells and provides O2 for the cascade reaction. Finally, the nanoparticles are camouflaged with osteosarcoma cell membranes, endowing the nanoparticles with homologous targeting and immune escape abilities. Both in vivo and in vitro evaluations reveal high synergistic therapeutic efficacy of M-mFeP@O2-G, with a desirable tumor-inhibition rate (90.50%), which indicates the great potential of this platform for clinical treating cancer.

Front Cover: Metal‐Organic‐Frameworks and Their Derived Materials in Photo‐Thermal Catalysis (Eur. J. Inorg. Chem. 28/2022)

The Front Cover shows the two routes in which metal-organic frameworks (MOFs) can participate in photo-thermal reactions. In the case of MOF-based composites, MOFs can act as hosts for plasmonic metal nanoparticles that, upon irradiation, are able to drive chemical reactions through high-energy electrons and/or thermal enhancement. In the case of MOF-derived materials, MOFs play a role as sacrificial templates to create new materials based on highly dispersed metal nanoparticles embedded into a carbon matrix. These latter materials benefit from the outstanding light-to-heat conversion and broadband absorption of carbon structures. Both approaches mentioned above represent promising pathways for the implementation of MOFs as photo-thermal catalysts for the production of solar fuels and chemicals. More information can be found in the Review by J. Gascon and co-workers.

Photothermal Suzuki Coupling Over a Metal Halide Perovskite/Pd Nanocube Composite Catalyst.

The development of improved catalysts capable of performing the Suzuki coupling reaction has attracted considerable attention. Recent findings have shown that the use of photoactive catalysts improves the performance, while the reaction mechanism and temperature-dependent performance of such systems are still under debate. Herein, we report Pd nanocubes/CsPbBr3 as an efficient catalyst for the photothermal Suzuki reaction. The photo-induced and thermal contribution to the overall catalytic performance has been investigated. Light controls the activity at temperatures around and below 30 °C, while thermal catalysis determines the reactivity at higher temperatures. The Pd/CsPbBr3 catalyst exhibits 11 times higher activity than pure CsPbBr3 at 30 °C due to reduced activation barrier and facilitated charge carrier dynamics. Furthermore, the alkoxide radicals (R-O-) for the Suzuki reaction are experimentally and theoretically confirmed, and photogenerated holes are proven to be crucial for cleaving C-B bonds of phenylboronic acids to drive the reaction. This work prescribes a general strategy to study photothermal catalysis and offers a mechanistic guideline for photothermal Suzuki reactions.

Cover Feature: Evidence of Kinetically Relevant Consistency in Thermal and Photo‐Thermal HCOOH Decomposition over Pd/LaCrO3/C3N4 Composite (Chem. Eur. J. 19/2022)

Together photo- and thermal energy promote catalytic reactions in a synergetic way. However, how light cooperates with thermal energy is still unclear. Here, C−H bond rupture within HCOOH* was determined to be the rate-determining step, with adsorbed CO* as the most abundant surface intermediate under both thermal and photothermal reaction conditions, as confirmed by kinetic isotopic effects and in-situ FTIR characterizations. Clear evidence of kinetically relevant consistency was found under both thermal and photothermal HCOOH decomposition reactions over a Pd/LaCrO3/C3N4 composite. More information can be found in the Research Article by H. Zhang et al. (DOI: 10.1002/chem.202104623).

In vitro degradation, photo-dynamic and thermal antibacterial activities of Cu-bearing chlorophyllin-induced Ca-P coating on magnesium alloy AZ31.

Surgical failures, caused by postoperative infections of bone implants, are commonly met, which cannot be treated precisely with intravenous antibiotics. Photothermal therapy (PTT) and photodynamic therapy (PDT) have attracted widespread attention due to their non-invasive antibacterial effects on tissues and no bacterial resistance, which may be an excellent approach to solve infections related to bone implants for biodegradable magnesium alloys. Herein, a sodium copper chlorophyllin (SCC) with a porphyrin ring induced Ca–P coating was prepared on AZ31 magnesium alloy via layer-by-layer (LbL) assembly. The morphology and composition of the samples were characterized through field emission scanning electron microscope (FE-SEM) with affiliated energy dispersive spectrometer (EDS), X-ray diffractometer (XRD), and Fourier infrared spectrometer (FTIR) and X-ray photoelectron spectrometer (XPS) as well. Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and hydrogen evolution experiments were employed to evaluate the corrosion behavior of the samples. Atomic absorption spectrophotometer was used to measure Cu elemental content of different immersion periods. Cytocompatibility and antibacterial performance of the coatings were probed using in vitro cytotoxicity tests (MTT assay), live/dead cell staining and plate counting method. The results showed that the obtained (Ca–P/SCC)10 coating exhibited good corrosion resistance, antimicrobial activity (especially under 808 nm irradiation) and biocompatibility. The antibacterial rates for E. coli and S. aureus were 99.9% and 99.8%, respectively; and the photothermal conversion efficiency was as high as 42.1%. Triple antibacterial mechanisms including photodynamic, photothermal reactions and copper-ions release were proposed. This coating exhibited a promising application for biodegradable magnesium alloys.

Photothermal methane coupling into liquid fuels with hydrogen evolution over nanocatalysts based on layered double hydroxide (LDH)

The increasing energy and environmental problems have made clean energy-driven catalysis a hot research topic. Methane is an earth-abundant raw material but difficult to be converted by thermochemical processes. It is of great significance to seek novel strategies to convert methane into high-value chemicals. Herein, we synthesize a series of transition metal catalysts based on layered double hydroxide precursors which were used for photothermal methane nonoxidative coupling reactions. The strong photothermal and chemisorption effects of the derived transition metal nanostructures allow the efficient activation of methane molecules. Among them, alumina-supported metallic Ni and NiCo-alloy catalysts show excellent methane nonoxidative coupling activities, achieved hydrogen production rates of 4816.53 μmol g−1 h−1 and 5130.9 μmol g−1 h−1, accompanied by liquid fuels production rates of 59.2 mg g−1 h−1 and 63 mg g−1 h−1, respectively. The findings, therefore, provide a new strategy for methane nonoxidative coupling driven by light energy at mild conditions.

Synthesis, characterization and density Functional theory (DFT) study of LaCeO3

Nanosized perovskite oxide of LaCeO3 was synthesized using the EDTA-citrate method and calcined at 600 °C for 5 h. The white powder obtained from synthesis was characterized using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Raman Spectroscopy, and UV–Vis Diffuse Reflectance Spectroscopy (UV–Vis DRS) Analysis. The developed perovskite can be used as catalyst in soot oxidation, VOC oxidation, and photo thermal reactions, and materials in solar cells, sensors and fuel cell. XRD analysis confirms the crystalline nature of the perovskite with a predominantly cubic fluorite structure. Morphological studies concluded that the LaCeO3 perovskite has a crystalline microstructure with a large number of honeycomb-like macropores with a minor crystalline phase. UV–Vis DRS tells us that the absorbance acquired can be attributed to the variations in the composition of Ce. Tauc plot allotted based on the data obtained from UV–vis Spectroscopy gave an energy band gap of 3.15 eV, signifying that the material may be classified as a semiconductor. Raman Spectroscopy tells us that the sharp peak obtained at 446 cm−1 corresponds to the stretching of the Ce-O bond. XPS analysis corresponds to La 3d with binding energy gap of 3.3 eV, Ce 3d with redox ratio 49.88% and O 1 s peak with surface oxygen vacancy ratio of 65.5%. DFT analysis of the sample result in direct band gap of 0.802 eV and indirect band gap of 1.716 eV.

Adhesive-free bonding of PI/PDMS interface by site-selective photothermal reactions

Effective bonding between polyimide (PI) and polydimethylsiloxane (PDMS) is important for the development of both implanted and externally mounted biomedical devices; however, achieving an adhesive-free bonding between the two materials without using surface chemical treatments has been largely unsuccessful to date. We discovered that, within a narrow range of laser parameters, laser-induced photothermal reactions at a specific site on the PI/PDMS interface led to an unexpected reinforcement of the adhesion strength between the two materials. This result was verified by microscopic in situ observations in which PDMS residues were observed to remain on the PI surface after forced delamination. The effect of heat pulses on the PI/PDMS interface was evaluated on the atomic scale through molecular dynamics simulations, and the results showed that as the heat pulses were added, the roughness values of both the PI and PDMS surfaces increased, accompanied by an improvement in the elastic properties at the interface, thus increasing the effective adhesion energy per unit area. The incorporation of a scanning scheme enabled the continuous bonding of the two materials, demonstrating that the proposed process can be easily scaled up for practical applications.

Photosensitive drug delivery systems for cancer therapy: Mechanisms and applications

Over the past three decades, various photosensitive nanoparticles have been developed as potential therapies in human health, ranging from photodynamic therapy technologies that have already reached clinical use, to drug delivery systems that are still in the preclinical stages. Many of these systems are designed to achieve a high spatial and temporal on-demand drug release via phototriggerable mechanisms. This review examines the current clinical and experimental applications in cancer treatment of photosensitive drug release systems, including nanocarriers such as liposomes, micelles, polymeric nanoparticles, and hydrogels. We will focus on the three main physicochemical mechanisms of imparting photosensitivity to a delivery system: i) photochemical reactions (oxidation, cleavage, and polymerization), ii) photoisomerization, iii) and photothermal reactions. Photosensitive nanoparticles have a multitude of different applications including controlled drug release, resulting from physical/conformational changes in the delivery systems in response to light of specific wavelengths. Most of the recent research in these delivery systems has primarily focused on improving the efficacy and safety of cancer treatments such as photodynamic and photothermal therapy. Combinations of multiple treatment modalities using photosensitive nanoparticulate delivery systems have also garnered great interest in combating multi-drug resistant cancers due to their synergistic effects. Finally, the challenges and future potential of photosensitive drug delivery systems in biomedical applications is outlined.

CO2 Footprint of Thermal Versus Photothermal CO2 Catalysis.

Transformation of CO2 into value-added products via photothermal catalysis has become an increasingly popular route to help ameliorate the energy and environmental crisis derived from the continuing use of fossil fuels, as it can integrate light into well-established thermocatalysis processes. The question however remains whether negative CO2 emission could be achieved through photothermal catalytic reactions performed in facilities driven by electricity mainly derived from fossil energy. Herein, we propose universal equations that describe net CO2 emissions generated from operating thermocatalysis and photothermal reverse water-gas shift (RWGS) and Sabatier processes for batch and flow reactors. With these reactions as archetype model systems, the factors that will determine the final amount of effluent CO2 can be determined. The results of this study could provide useful guidelines for the future development of photothermal catalytic systems for CO2 reduction.

Effect of continuous wave, quasi-continuous wave and pulsed laser radiation on functional characteristics of fish spermatozoa

For the first time, using sturgeon sperm as a model system, sensitive to optical radiation, the comparative studies of biological effect of continuous wave, quasi-continuous wave, nano- and picosecond laser radiation under conditions with equal average irradiance (3 mW/cm2) and wavelength (532 nm) have been carried out. Analyzing the parameters of spermatozoa motion it has been shown that, depending on the energy dose and mode of laser operation, the radiation may have both stimulatory and inhibitory effect on the velocity of motion and spermatozoa motility duration as well as on sustaining of functional characteristics of cold-stored sperm. The possibility of increasing the fertilization rate due to use of the sperm preliminary treated with laser radiation is demonstrated. For the first time, the possibility of enhancement of biological effect going from continuous wave to quasi-continuous wave laser radiation at equal irradiance and wavelength has experimentally been proven. It is shown that the difference in biological effect of continuous wave, quasi-continuous wave, nano- and picosecond laser radiation is due to amplitude (peak) values of intensity. Using fluorescence analysis and luminol-dependent chemiluminescence assay, evidence for the participation of endogenous flavins and metal-free porphyrins in sensitized ROS formation (singlet oxygen, hydrogen peroxide, and hydroxyl radicals) in sturgeon sperm was obtained. Mechanisms of photochemical and photothermal reactions explaining the difference in efficacy of action of laser radiation in above modes are discussed.

Bi-functional particles for integrated thermo-chemical processes: Catalysis and beyond

Particulate materials possessing dual functionalities have received tremendous investigations in many fields, owing to their superiority over mono-functional counterparts and their potential for process integration and intensification. This review focuses on bi-functional catalytic particles which also serve as sorbents/adsorbents or heat suppliers in the scheme of various thermo-chemical processes, enabling inherent separation or energy conservation within single-step operation. Bi-functional particles applied for integration of reaction and separation including sorption-enhanced hydrogen production and integrated capture and catalytic conversion processes are reviewed in detail, providing insights into material design and key performance indicators. On the other hand, bi-functional particles applied for integration of reaction and non-thermal radiation heating, including electrothermal and photothermal assisted heterogeneously catalyzed reactions, are also reviewed, with emphasis on the material property and energy efficiency improvement. These bi-functional particles show broad adaptability and feasibility in various reactions operated in integrated and intensified schemes, affording huge potentials for further improving productivity and efficiency in thermo-chemical processes.

Electrochemical sensor for nitrite detection in water samples using flexible laser-induced graphene electrodes functionalized by CNT decorated by Au nanoparticles

This paper reports on a sensitive, selective and reproducible electrochemical sensor for nitrite detection based on laser-induced graphene (LIG) electrode patterned onto a flexible poly(imide) substrate and further modified by COOH functionalized multiwalled carbon nanotubes (f-MWCNT) and gold nanoparticles (AuNPs) films. According to Raman spectroscopy, photoluminescence spectroscopy and scanning electron microscopy, the laser induced photothermal reactions produce ultrathin graphene-like sheets emerging from the substrate, which stay connected to the surface forming a three-dimensional microporous structure. This process permits to scribe in a single step and mask-free, working, counter and reference electrodes on a polymeric substrate. Cyclic voltammetry and electrochemical impedance spectroscopy performed in ferri-ferrocyanide redox pair show that the electroactive area of LIG modified by f-MWCNT- AuNPs is increased and the charge-transfer resistance is diminished in comparison to the modification by each nanomaterial alone. The sensor has a linear characteristic (R2 = 0.996) in the nitrite concentration range from 10 μM to 140 μM and a limit of detection of 0.9 μM following the 3Sb/m method. In presence of typical interfering ions, added in 100-fold excess, the sensor shows a relative standard deviation less than 10%. The results show that a single LIG/f-MWCNT-AuNPs electrode can perform electrochemical detection of nitrite for at least seven consecutive runs with a low signal variation of 2.63% corresponding to a nitrite concentration of 90 μM. Furthermore, seven different electrodes fabricated in the same batch performed identically, with a low signal variation of 2.80% corresponding to a nitrite concentration of 90 μM.

Effect of temperature on the photoreactions of ethanol over Ag/TiO2 in steady state catalytic conditions

The photo-thermal reaction of ethanol to hydrogen and acetaldehyde over Ag/TiO2 is studied in flow conditions. Hydrogen production is mostly photo driven below 170 °C, and thermally driven above 250 °C. An increase in the overall reaction rates is observed when both photons and heat (photo-thermal effect) are present in the 125−225 °C temperature window for acetaldehyde and hydrogen production (via ethanol dehydrogenation; C2H5OH → CH3CHO + H2). The activation energies for photo-thermal and thermal reactions, measured in steady state conditions, are 31 and 40 kJmol−1, respectively. The maximum enhancement in reaction rates is 1.5× for acetaldehyde and 10× for hydrogen production. The enhancement for these two product should be the same. Reasons for these discrepancies are discussed. Other minor reaction products including ethylene and acetone appeared above 225 °C. Possible reasons for the enhanced rate of ethanol reaction under photo-thermal conditions, linked to plasmon resonance of Ag particles of Ag/TiO2, are discussed. Light to Chemical Energy Conversion (LCEC) was found equal to 0.12 % and 0.25 % at 170 °C and 225 °C, respectively.

Nanostructured Medical Adhesives.

Suturing has been the gold standard approach to close wounds for many decades. However, suturing causes tissue damage, which is accompanied by foreign body reaction, entry of pathogens, complications, infection, or death. In addition, the procedure is usually time-consuming, requiring manual dexterity and free moving space. Other adhesive approaches have been proposed and demonstrated with great potential, including laser-assisted tissue closure with either photothermal or photochemical reactions, application of nanoparticles, glues, constructs based on extracellular matrix (ECM), microbarbs, bio-inspired structures, and tape. The quality of closure has been evaluated by histological methods, indexing, morphology, tensile testing, patency rate, leakage pressure, and burst pressure. All the novel tissue joining methods aim to provide an adhesive with appropriate strength, non-cytotoxicity, and minimal damage. The capability for rapid attachment and release may further reduce surgical procedure time. More research is needed to prove the feasibility of new tissue joining techniques based on the type of tissue, surface chemistry, and working environment.

Modeling the effect of Cu doped TiO2 with carbon dots on CO2 methanation by H2O in a photo-thermal system

The process of CO2 reduction by H2O is always restricted due to its non-spontaneous in thermodynamic. In this work, a photo-thermal coupled device is designed to obtain a high-achievement CO2 methanation by H2O over carbon dots (CDs) drafted Cu/TiO2 (Cu/TiO2-C). Dramatic promotion of CH4 production exhibits under UV irradiation at a higher temperature (>150 °C), but a poor photo-promotion at room temperature. In-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and isotopic-label temperature programmed surface reaction (TPSR) suggest that CO2 methanation process over Cu/TiO2-C can be regarded as two main spontaneous process: CO2 is firstly reduced by Cu(I) (Cu2O) to CO (CO2 + Cu2O → CO +CuO), then CO is reduced by H2O to CH4 via water-gas shift (WGS) process. Here, CDs not only act as electron storage to keep the presence of Cu(I) (from Cu(II) to Cu(I) not to Cu (0)) at a high temperature, but also capture the photo-generated holes from TiO2 induced by UV light, resulting in the cycle of Cu (I)/ Cu(II) with concomitant of electron storage and release. The synergy effect of UV light and temperature do not occur on the Cu/TiO2 sample without CDs. Here, Cu (II) is mainly reduced by H2 pretreatment to Cu (0), while the poor cycle of Cu(I)/Cu(II) was exhibited under UV irradiation. This study shows that this non-spontaneous reaction could be designed as two ongoing spontaneous processes by adding UV light, this approach may apply to other photo-thermal reactions.

Thermodynamic processes on a semiconductor surface during in‐situ multi‐beam laser interference patterning

Laser interference has been widely used to produce one-dimensional gratings and more recently has shown great potential for two-dimensional patterning. In this study, the authors examine by simulation, its application to in-situ patterning during materials growth. To understand the potential, it is important to study the surface processes resulting from the laser–matter interaction, which have a key influence on the resulting growth mechanisms. In this work, the intensity distribution and the laser–semiconductor interaction resulting from four-beam interference patterns are analysed by numerical simulations. In particular, the authors derive the time and spatially dependent thermal distribution along with the thermal-induced desorption and surface diffusion. The results provide a crucial understanding of the light-induced thermal profile and show that the surface temperature and the surface adatom kinetics can be controlled by multi-beam pulsed laser interference patterning due to photothermal reactions. The approach has potential as an in-situ technique for the fast and precise nanostructuring of semiconductor material surfaces.

Direct laser writing of graphene films from a polyether ether ketone precursor

Graphene-based micro-supercapacitors exhibit excellent electrochemical performance that can easily meet the energy storage requirements of micro-electronic products. However, the complex preparation and transfer process steps of traditional preparation methods limit their wide application. Direct laser writing can deposit graphene laser-induced graphene (LIG) onto a specific substrate-patterned electrodes. This approach offers great advantages in the preparation of miniature and complex-patterned electrodes, but currently there is a limited choice of precursor materials. In this reported study, biocompatible polyether ether ketone (PEEK) was irradiated using a high repetition rate picosecond laser to produce graphene. Various photothermal and photochemical reactions were involved in the one-step conversion of PEEK into a film comprised of a several layers (3–4) of graphene. The electrochemical testing of a three-electrode system containing this novel graphene showed that LIG had a specific capacitance of 20.4 mF cm−2 at a scan speed of 10 mV s−1, and the capacitance was reversibly maintained with 89.37% retention of the initial capacitance after 5000 cycles. The novel LIG with higher specific capacitance and cycle stability has great potential for use in energy storage micro-devices.