Reduction In Activity Research Articles

Subtle Modifications in Interface Configurations of Iron/Cobalt Phthalocyanine-Based Electrocatalysts Determine Molecular CO2 Reduction Activities.

Strain engineering has emerged as a powerful approach in steering material properties. However, the mechanism and potential limitations remain poorly understood. Here we report that subtle changes in molecular configurations can profoundly affect, conducively or adversely, the catalytic selectivity and product turnover frequencies (TOFs) of CO2 reduction reaction. Specifically, introducing molecular curvature in cobalt tetraaminophthalocyanine improves the multielectron reduction activity by favorable *CO hydrogenation, attaining methanol Faradaic efficiency up to 52 %. In stark contrast, strained iron phthalocyanine exacerbates *CO poisoning, leading to decreased TOFCO by >50 % at -0.5 VRHE and a rapid current decay. The uniform dispersion is crucial for optimizing electron transfer, while activity is distinctly sensitive to the local atomic environment around the active sites. Specifically, local strain either enhances binding to intermediates or poisons the catalytic sites. Our comprehensive analysis elucidates the intricate relationship between molecular structure and activities, offering insights into designing efficient heterogeneous molecular interfaces.

Electrochemical Deposition of Silver Nanoparticle Assemblies on Carbon Ultramicroelectrode Arrays.

Silver nanoparticle (AgNP) assemblies combined with electrode surfaces have a myriad of applications in electrochemical energy storage and conversion devices, (bio)sensor development, and electrocatalysis. Among various nanoparticle synthesis methods, electrochemical deposition is advantageous due to its ability to control experimental parameters, enabling the formation of low-nanoscale (<10 nm) particles with narrow size distributions. Herein, we report the electrodeposition of AgNPs on a unique electrode platform based on carbon ultramicroelectrode arrays (CUAs), exploring several experimental variables including potential, time, and silver ion concentration. Extensive scanning electron microscopy analysis revealed that more reductive deposition potentials resulted in higher counts of smaller-sized AgNPs. While previous studies have employed planar, macro-sized electrodes with millimolar silver ion concentrations and minute-long times for AgNP electrodeposition, our results demonstrate that lower Ag+ concentrations (50-100 µM) and shorter deposition times (15-30 s) are sufficient for successful AgNP formation on CUAs. These findings are attributed to enhanced mass transfer from the radial diffusion of the array-based CUAs. The quantity of deposited Ag was determined to be 1100 ± 200 nmol cm-2, consistent with AgNP-modified CUA electrocatalytic activity for hydrogen peroxide reduction. This study emphasizes the importance of carefully considering AgNP electrodeposition parameters on unconventional electrode surfaces.

Substitution of the Axial Type 1 Cu Ligand Affords Binding of a Water Molecule in Axial Position Affecting Kinetics, Spectral, and Structural Properties of the Small Laccase Ssl1.

Multicopper oxidases use Cu ions as cofactors to oxidize various substrates. High reduction potential at Type 1 Cu is considered as crucial for effective catalysis. Previous studies have shown that replacing the axial methionine ligand of the Type 1 Cu with leucine or phenylalanine leads to an increased reduction potential, but not always to higher enzyme activity. Here we present a study on six variants of the small laccase Ssl1 from Streptomyces sviceus, where the axial methionine ligand was substituted, and the effect of the axial ligand on reduction potential, activity, spectral properties and structure was investigated. Absorption, electronic circular dichroism and EPR spectra revealed the presence of a stronger coordinating axial ligand like oxygen, which influences the electronic and catalytic properties more than the nature of the amino acid side chain. The crystal structures of the Ssl1 variants were solved, which show that none of the amino acid side chains coordinate to the Cu. Instead, a water molecule is found in the axial coordination site, which support the spectroscopic data. Our findings highlight the importance of combining structural and spectroscopic methods to investigate the effect of amino acid exchange on multicopper oxidases.

First report, phytochemical screening, and antioxidant and acetylcholinesterase inhibition activities of Macrolepiota mastoidea (Fr.) Singer mushroom extract in the Southwest region of Brazil

The Agaricales family is rich in species of edible macrofungi. Macrolepiota mastoidea is a representative of this group, found in various regions of the world, including Brazil. It is an edible species with several recorded biological activities. This study aimed to report the first findings on M. mastoidea and its phytochemical screening, as well as its antioxidant activity and acetylcholinesterase inhibition in a 70% (v/v) hydroethanolic extract from fresh mushrooms. M. mastoidea was collected from a Cerrado area in the Southwest of Goiás, Brazil. The hydroethanolic extract was produced, and the phytochemical screening was conducted for various phytochemical groups. Antioxidant activity was assessed using the DPPH free radical model, and acetylcholinesterase inhibition activity was determined using Electrophorus electricus type VI. The results showed the presence of various phytochemical groups such as alkaloids, sugars, flavonoids, and tannins. The DPPH reduction activity was IC50 305.16 µg mL-1, and acetylcholinesterase inhibition was 72%. Macrolepiota mastoidea demonstrated potential for further pharmacological studies with promising biological activities.

Subtle Tuning of Catalytic Well Effect in Phthalocyanine Covalent Organic Frameworks for Selective CO2 Electroreduction into C2H4.

In the electrocatalytic CO2 reduction reaction (CO2RR), the strategic design of a catalytic well capable of regulating the overall confinement effects of catalytic sites holds significant promise for enhancing multiple-electron transfer and C─C coupling efficiency, particularly for the generation of C2+ products. Here, a series of Cu-salphen-based covalent organic frameworks (COFs) featuring hydroxyl-induced catalytic well are synthesized, which demonstrate successful application in electrocatalytic CO2RR to yield multiple-electron transferred products. The meticulously engineered catalytic well, facilitated by multi-hydroxyl groups, manifests robust confinement effects, facilitating selective adsorption, enrichment, and activation of CO2, intermediate stabilization, and reduction of energy barriers for electrocatalytic CO2RR. Specifically, product selectivity can be finely tuned from CH4 to C2H4 by modulating the levels of catalytic well, with CuPc-DFP-4OH-Cu exhibiting the most pronounced catalytic well effect, yielding a high 56.86% faradaic efficiency (FE) for C2H4 at -0.7 V, while CuPc-DFP-Cu, with the weakest catalytic well effect, achieves a 75.24% FE for CH4 at -1.0 V. Notably, the attained FE for C2H4 (56.86%) surpasses that of all reported COFs to date. Complemented by theoretical calculations and in situ tests, this study delves deeply into the pivotal roles of hydroxyl-induced catalytic well with confinement effects.

B and P dual sites co-modified g-C3N4 p–n homojunction for photocatalytic CO2 reduction coupled with metronidazole oxidation

The limited active sites and sluggish reaction kinetics greatly restrict the photocatalytic redox activity for CO2 reduction coupled with metronidazole (MNZ) oxidation. Herein, the electron rich P and electron deficient B were synergistically anchored on graphitic carbon nitride for constructing BPCN p − n homojunction with isolated B and P redox dual − sites, which exhibits an excellent CO yield rate of 3.811 μmol g−1h−1 coupled with outstanding MNZ removal rate of 92.60 %. The improvement of photocatalytic redox performance was mainly attributed to two aspects: On the one hand, the construction of p − n homojunction effectively accelerated the separation and migration of carriers; On the other hand, the B and P redox dual − sites availably reduced the reaction energy barrier of CO2 reduction and MNZ oxidation, respectively. Besides, the dual − functional coupled reaction system realized the full utilization of photogenerated charges. This work not only offers new insight for designing efficient p − n homojunction with redox double sites, but also confirms the potential application for congenerous environment renovation and energy conversion.

WS2/WN interface-triggered energetic triiodide reduction activity to enhance performance of solar cells

The sluggish triiodide reduction activity poses a significant challenge that hinders the acquisition of high efficiency in dye-sensitized solar cells (DSSCs). Herein, a one-step thermal reduction strategy is adopted to in situ construct a two-dimensional layered WS2/WN heterostructure and couple it onto N-doped carbon spheres (labeled as WS2/WN-NC). The constructed DSSC with WS2/WN-NC counter electrode (CE) reaches as high as power conversion efficiency (PCE) of 9.52 %, surpassing that of pure Pt (8.33 %). Theoretical calculations combined with X-ray photoelectron spectroscopy (XPS) analysis reveal that electrons can easily induce the transfer of electrons from WS2 to WN and regulate the charge states of WS2 and WN, concentrating abundant electrons at the WS2/WN interface, which is conducive to inhibiting the coupling of iodide ions. Electron microscopy reveals that the layered WS2/WN adheres to the N-doped carbon spheres, which can prevent stacking and thereby accelerate the electron transport rate. Additionally, due to the supporting role of the carbon spheres, the WS2/WN active substances can be fully utilized, thereby enhancing the triiodide catalytic activity. Therefore, the structure-activity relationship between the two can complement and enhance each other, thereby optimizing the DSSC reaction kinetics and enhancing the photoelectric conversion efficiency and stability.

Multifunctional curcumin/γ-cyclodextrin/sodium chloride complex: A strategy for salt reduction, flavor enhancement, and antimicrobial activity in low-sodium foods

Excessive salt consumption is strongly linked to the chronic diseases development, highlighting the urgent need for effective salt-reduction strategies in food products. However, reducing salt content often compromises both food preservation and flavor. In this study, we hypothesized that curcumin could enhance the flavor perception of sodium chloride while compensating for its antimicrobial effect in reduced-salt applications. To test this, we developed a curcumin/γ-cyclodextrin/sodium chloride complex (IC), using γ-cyclodextrin as a carrier, and evaluated its antimicrobial and flavor-enhancing properties. The complex's formation was confirmed through various analytical techniques. Results from electronic tongue and sensory evaluations demonstrated that the IC enhanced the perception of saltiness and imparted unique aromatic characteristics compared to standard sodium chloride. GC-IMS analysis identified key aroma contributors, such as aldehydes and alcohols. Additionally, antimicrobial tests revealed that the IC efficiently mediated the sono/photodynamic inactivation of Shewanella putrefaciens and Vibrio parahaemolyticus. In summary, the IC offers a multifunctional approach, enhancing flavor, reducing salt, and enabling antimicrobial activity, while promoting practical uses of sono/photodynamic technology in low-sodium foods.

Introducing yttrium into Pt-based intermetallic compounds induce electron perturbation and anti-oxidation for enhancing oxygen reduction activity and durability

Pt-based intermetallic compounds (IMCs) as competitive electrocatalysts for oxygen reduction reaction (ORR) still face problems of surface oxidation and transition metal (M) dissolution in harsh electrochemical environments. Here, we report a strategy to induce electronic perturbation in IMCs by introducing yttrium (Y) to further regulate Pt d-band filling and alloy stability, and Y-doped PtCo IMCs supported on π-electron-rich nitrogen-doped porous carbon (Y-PtCo/NPPC) are presented as a proof of concept. X-ray absorption fine structure (XAFS) reveals that the introduced Pt-O-Y configuration in PtCo IMCs allows the Pt 5d orbital occupancy to be increased, which enhances the anti-oxidation ability of Pt atoms and further stabilizes the internal Co atoms. Y-PtCo/NPPC exhibits satisfactory ORR activity with a high mass activity (MA) of 1.89 A mgPt-1 and is much higher than that of the Pt/C catalyst (0.19 A mgPt-1). In particular, the MA retention of up to 84.7 % is maintained after 30,000 cycles accelerated durability test (ADT), and the Co atom dissolution ratio decreased by 6.4 times compared to PtCo/NPPC. Impressively, the Y-PtCo/NPPC catalyst achieves a high peak power density (1.0 W cm−2) in proton exchange membrane fuel cell (PEMFC) (H2-air). Theoretical calculations have also demonstrated that the introduction of Y element shifts Pt d-band downward, weakening the adsorption of oxygen-containing intermediates. The improved stability stems from the enhancement of the vacancy formation energies of Pt and Co.

Single-Atom-Layer Metallization of Plasmonic Semiconductor Surface for Selectively Enhancing IR-Driven Photocatalytic Reduction of CO2 into CH4.

Efficient harvesting and utilization of abundant infrared (IR) photons from sunlight is crucial for the industrial application of photocatalytic CO2 reduction. Plasmonic semiconductors have significant potential in absorbing low-energy IR photons to generate energetic hot electrons. However, modulating these hot electrons to selectively enhance the activity of CO2 reduction into CH4 remains a challenge. Herein, the study proposes a single-atom-layer (SAL) metallization strategy to enhance the generation of IR-driven hot electrons and facilitate their transfer from plasmonic semiconductors to CO2 for producing CH4. This strategy is demonstrated using a paradigmatic W18O49@W-Sn nanowire array (NWA), where Sn2+ ions are grafted onto exposed O atoms on the surface of plasmonic W18O49 to form a surface W-Sn SAL. The incorporation of Sn single atoms enhances plasmonic absorption in IR light for W18O49 NWA. The W-Sn SAL not only promotes CO2 adsorption and reduces its reaction activation energy barrier but also shifts the endoergic CO-protonation process toward an exoergic reaction pathway. Thus, the W18O49@W-Sn NWA exhibits >98% selectivity for IR-driven CO2 reduction to CH4 with an activity over 9.0 times higher than that of bare W18O49 NWA. This SAL metallization strategy can also be applied to other plasmonic semiconductors for selectively enhancing CO2-to-CH4 reduction reactions.

Novel Single Perovskite Material for Visible-Light Photocatalytic CO2 Reduction via Joint Experimental and DFT Study.

Developing advanced and economically viable technologies for the capture and utilization of carbon dioxide (CO2) is crucial for sustainable energy production from fossil fuels. Converting CO2 into valuable chemicals and fuels is a promising approach to mitigate atmospheric CO2 levels. Among various methods, photocatalytic reduction stands out for its potential to reduce emissions and produce useful products. Here, novel perovskite ZnMoFeO3 (ZMFO) nanosheets are presented as promising semiconductor photocatalysts for CO2 reduction. Experimental results show that ZMFO has a narrow bandgap, exceptional visible light response, large specific surface area, high crystallinity, and various surface-active sites, leading to an impressive photocatalytic CO2 reduction activity of 24.87 µmolg-1h-1 and strong stability. Theoretical calculations reveal that CO2 conversion into CO and CH4 on the ZMFO surface follows formaldehyde and carbine pathways. This study provides significant insights into designing innovative perovskite oxide-based photocatalysts for economical and efficient CO2 reduction systems.

Leveraging interlocking structural defects of g-C3N4/CNT networks: Toward enhanced oxygen reduction activity of the cobalt-based electrocatalyst

Carbon-based transition-metal electrocatalysts are regarded as promising candidates for catalyzing oxygen reduction reaction (ORR), yet their electrocatalytic ORR performances are greatly limited by active sites utilization caused by the metal aggregation and pore collapse under high temperature. This study rationally designed a cobalt-based ORR catalyst supported on a g-C3N4/carbon nanotube (CNT) network as a cost-effective alternative of platinum-based catalysts. CNT were embedded into the lamellar precursor of melamine and cyanuric acid, and a synergistic effect between CNT and precursor was realized to regulate the density and activity of active sites. The polycondensation of precursors led to the formation of an "interlocking" structure of CNT supports with abundant exposed defects, allowing for effectively anchoring cobalt ions to generate Co-Nx sites. Meanwhile, partial Co ions underwent reconstruction and transportation to form Co nanoparticles and extended the disruptive CNT structure, exposing more interfacial defects to enhance the ORR catalytic properties. The prepared Co@g-C3N4/CNT catalyst demonstrated impressive ORR activity comparable to commercial Pt/C catalyst, showing superior stability. This research offers a promising approach for engineering interfacial defects to synthesize high-performance non-precious metal electrocatalysts for energy conversion applications.

Photocatalytic Substrate Oxidation Catalyzed by a Ruthenium(II) Complex with a Phenazine Moiety as the Active Site Using Dioxygen as a Terminal Oxidant.

We have developed photocatalytic oxidation of aromatic substrates using O2 as a terminal oxidant to afford only 2e--oxidized products without the reductive activation of O2 in acidic water under visible-light irradiation. A RuII complex (1) bearing a pyrazine moiety as the active site in tetrapyrido[3,2-a:2',3'-c:3″,2″-h:2‴,3‴-j]phenazine (tpphz) as a ligand was employed as a photocatalyst. The active species for the photocatalysis was revealed to be not complex 1 itself but the protonated form, 1-H+, protonated at the vacant diimine site of tpphz. Upon photoexcitation in the presence of an organic substrate, 1-H+ was converted to the corresponding dihydro-intermediate (2-H+), where the pyrazine moiety of the ligand received 2e- and 2H+ from the substrate. 2-H+ was facilely oxidized by O2 to recover 1-H+. Consequently, an oxidation product of the substrate and H2O2 derived from dioxygen reduction were obtained; however, the H2O2 formed was also used for oxidation of 2-H+. In the oxidation of benzyl alcohol to benzaldehyde, the turnover number reached 240 for 10 h, and the quantum yield was determined to be 4.0%. The absence of ring-opening products in the oxidation of cyclobutanol suggests that the catalytic reaction proceeds through a mechanism involving formal hydride transfer. Mechanistic studies revealed that the photocatalytic substrate oxidation by 1-H+ was achieved in neither the lowest singlet excited state nor triplet excited state (S1 or T1) but in the second lowest singlet excited state (S2), i.e., 1(π-π*)* of the tpphz ligand. Thus, the photocatalytic substrate oxidation by 1-H+ can be categorized into unusual anti-Kasha photocatalysis.

Metabolic coupling of aerobic methane oxidation and short-cut nitrification and denitrification for anaerobic effluent treatment in photo-sequencing batch biofilm reactor

This study explored the use of algae to supply oxygen in situ as an alternative to mechanical aeration for anaerobic effluent treatment in a photo-sequencing batch biofilm reactor (PSBBR). By establishing alternating aerobic (dissolved oxygen (DO) > 2 mg /L)/anoxic conditions (<0.5 mg-DO/L) through a 6-h off/6-h on biogas sparging cycle and continuous illumination (1500–3000 lux), the PSBBR achieved a significant ammonia removal rate of 15–25 mg N L−1d−1. This system demonstrated robust partial nitrification and nitrite reduction activities, coupled with aerobic methane oxidation. Metagenomic analysis revealed the enrichment of key microbial groups, including Leptolyngbyaceae, Methylocystis, Nitrosomonas and Hyphomicrobium. The key functional genes of methane (mmo, mdh, gfa, frm and fdh) and nitrogen (amo, hao, narGHI, and napAB) metabolisms were identified, while notably lacking nitrite oxidation genes. In conclusion, this study provides a promising post-treatment approach for anaerobic effluent through integrating biogas utilization with efficient nitrogen removal.

Enhancing Internal Electric Field of Metal-Free Donor-Acceptor Conjugated Photocatalysts for Efficient Photocatalytic Degradation of Tetracycline and CO2 Reduction.

Constructing alternating donor-acceptor (D-A) units within g-C3N4 represents an effective strategy for enhancing photocatalytic performance through improved charge carrier separation while concurrently addressing energy shortages and facilitating wastewater remediation. Here, a series of D-A-type conjugated photocatalysts (CNBTC-X) are prepared using g-C3N4 as an acceptor unit and different masses of 5-bromo-2-thiophenecarboxaldehyde (BTC) as a donor unit by a one-step thermal polymerization. CNBTC-50 presents higher photocatalytic properties for CO2 reduction coupled with tetracycline (TC) removal than those of g-C3N4, CNBTC-10, CNBTC-30, and CNBTC-70. The introduction of the unique electron-donor-acceptor structure effectively drives the separation and transfer of photoinduced carriers while reducing the internal carrier transfer hindrance. Photocatalytic experiments reveal that the CNBTC-50 photocatalyst achieves up to 94.6% TC removal under visible light irradiation conditions. Compared with that of the pristine g-C3N4, the photocatalytic degradation reaction rate constant of CNBTC-50 is significantly increased by about 3.87 times. The study examines the influence of various reaction parameters on degradation activity, including catalyst concentration, pH, and TC concentration. Additionally, LC-MS is utilized to perform a comprehensive analysis of the intermediates and pathways involved in TC degradation. Furthermore, CNBTC-50 demonstrates remarkable photocatalytic CO2 reduction activity, achieving rates of 20.83 μmol g-1 h-1 (CO) and 9.36 μmol g-1 h-1 (CH4), which are 10.68 and 5.98 times more efficient than those of g-C3N4, respectively. This work aims to offer valuable guidance for the rational design of nonmetal D-A-structured catalysts and effectively integrates reaction systems to couple CO2 reduction with antibiotic removal.

Integration of Cu2O-NiTiO3 as an efficient p-n heterojunction visible light photocatalytic system for the simultaneous removal of Cr (VI) and Alizarine Cyanine Green dye

Cu2O loaded NiTiO3 based p-n heterojunction photocatalysts of various proportions have been synthesized by liquid phase reduction process resulting in NiTiO3 nanoparticles dispersed on the surface of Cu2O. Formation of both oxide phases is confirmed from the XRD, HR-SEM and XPS analysis. Heterojunction formation is confirmed by the intimate contact between NiTiO3 and Cu2O as evidenced by HR-TEM. UV-Vis spectra exhibit a red shift indicating the extended visible light absorption. XPS shows the presence of oxidation states of Ni2+, Ti4+, Cu+, Cu2+ and O2-. Heterojunction materials showed enhanced activity for the simultaneous photocatalytic reduction of Cr (VI) and degradation of Alizarine Cyanine Green dye under visible light irradiation. 1:2 ratio of Cu2O and NiTiO3 heterojunction (1C:2N) material exhibits 100% dye degradation in 90 minutes and Cr (VI) reduction in 180 minutes. Higher activity of Cu2O-NiTiO3 p-n heterojunction is ascribed to the effective charge separation and extended visible light absorption

Hydrogen- assisted synthesis of defective triazine/heptazine homostructured nanosheets for efficient CO2photoreduction.

Homostructure construction has been demonstrated to be an effective way for boosting the photocatalytic activity of polymeric carbon nitride. However, the contribution of the intrinsic activity of molecular fragments in the catalytic performance of homostructured carbon nitride is yet to be explored. In this paper, a facile hydrogen-assisted strategy was used to synthesize triazine/heptazine intermolecular homojunctions (g-C3N4(MU-H)) with an ultrathin and defective structure, via the co-pyrolysis of melamine and urea precursors. Experimental characterizations and theoretical calculations revealed the copolymerization of triazine- and heptazine-based carbon nitride generated a homostructured interface with a large build-in electric field for efficient separation of photogenerated carriers. Due to the synergestic effect between the homostructured interface and nitrogen vacancies, as-synethesized g-C3N4(MU-H) exhibited an outstanding activity for photocatalytic CO2 reduction, with a CO yield rate of 14.45 μmol h-1, which was 23.5 and 3.64 times higher than those of bulk g-C3N4 and g-C3N4(M-H) synthesized from a single precursor, respectively. This study provides a new avenue for optimizing the charge separation efficiency of CO2 photoreduction catalysts by constructing intramolecular homojunction.

Designing S-scheme heterojunction via in situ converting partial NH2-MIL-68 into defective In2O3 for photocatalytic CO2 reduction

Intrinsic characteristics of metal–organic frameworks (MOFs) make them become promising candidates for the application of photocatalytic CO2 reduction. However, their photocatalytic activities are still unsatisfactory due to serious recombination of photogenerated charge carriers and insufficient light absorption. S-scheme heterojunction has demonstrated high superiority in the separation of charge carriers due to its unique structure and interface interaction. Nevertheless, it is difficult to construct it in MOF-based photocatalysts because of high interface connection requirements. Herein, a NH2-MIL-68 (In-MOF) is chosen as the research object. S-scheme heterojunction (In2O3@In-MOF) with oxygen vacancies (OVs) is easily constructed via in situ converting partial In-MOF into defective In2O3. The in-situ derivatization strategy is similar to epitaxial crystal growth, which could avoid drastic changes in the morphology of epitaxial growth rh-In2O3 to ensure the high-quality interface connection. The S-scheme heterojunction not only enhances the separation efficiency of photogenerated charge carriers of In-MOF, but also maintains the high reduction power of its photogenerated electrons as well as expanding its light absorption capacity. Therefore, In2O3@In-MOF exhibits enhanced photocatalytic CO2 reduction activity compared to those of pure In-MOF and In2O3. This work may open a potential pathway for the S-scheme heterojunction designing in the field of photocatalytic CO2 reduction.

UV–visible-infrared light driven photothermal synergistic catalytic reduction of CO2 over Cs3Bi2Br9/MoS2 S-scheme photocatalyst

Photothermocatalytic CO2 reduction has been considered as a green and sustainable strategy for solar-to-fuel conversion, since it can utilize the solar energy to simultaneously provide heat input and produce photogenerated charge carriers. To this end, exploring photothermal catalysts with broad-band absorption, high photo-heat conversion and charge separation efficiency is highly desirable. In this work, an innovative Cs3Bi2Br9/MoS2 (CBB/MoS2) composite has been elaborately constructed to investigate the photothermocatalytic performance towards CO2 reduction. In this composite, MoS2 plays dual roles: with photoinduced self-heating effect, it can act as an extra heater to accelerate the catalytic reaction, and meanwhile serves as a cocatalyst to promote charge separation by forming S-scheme heterojunction with CBB. As expected, the developed CBB/MoS2 composite delivered outstanding photothermocatalytic activity for CO2 reduction without any extra heat input, with the CO production rate reaching 172.79 μmol g−1h−1. As confirmed by experimental tests and theoretical calculations, the superior photothermocatalytic CO2 reduction performance of CBB/MoS2 was attributed to the synergetic effect of high photo-thermo transformation efficiency and highly improved charge separation. The present work offers a potential strategy for developing highly-efficient photothermal catalysts used in artificial photosynthesis.

Enrichment and catalysis effect of 2D/2D g-C3N4/Ti3C2 for promoting organic matter degradation and heavy metal reduction in plasma systems: Unveiling the promotion and redox mechanism

This work proposes a novel plasma-assisted 2D/2D g-C3N4/Ti3C2 system for treatment of organics-heavy metals composite wastewater. Unlike traditional materials in plasma system, 2D/2D g-C3N4/Ti3C2 not only improved the mass transfer efficiency of plasma by gathering both reactive species and pollutants onto the surface, but also induced photocatalytic reactions. Besides, the higher specific surface area and faster carrier separation rate can enhance the oxidation and reduction activity, and then promoted organic matter degradation and heavy metal reduction. Remarkably, the removal efficiency of sulfamethoxazole (SMX) and Cr(VI) increased by 16.5 % and 73.1 % respectively when introducing 2D/2D g-C3N4/Ti3C2. Roles of·OH,·H,·O2-, 1O2, e-, and h+ in SMX oxidation and Cr(VI) reduction are clarified. The primary aggregated·OH and 1O2 dominate the degradation of SMX. The influencing factors, synergistic mechanism between plasma and catalyst, and redox mechanism were clarified. This work provides a breakthrough idea for treatment of organics-heavy metals composite wastewater.