Metal-based Catalysts Research Articles

Manipulation of d-Orbital Electron Configurations in Nonplanar Fe-Based Electrocatalysts for Efficient Oxygen Reduction.

Manipulation of the spin state holds great promise to improve the electrochemical activity of transition metal-based catalysts. However, the underlying relationship between the nonplanar metal coordination environment and spin states remains to be explored. Herein, we report the precise regulation of nonplanar Fe atomic d-orbital energy level into an irregular tetrahedral crystal field configuration by introducing P atoms. With the increase of P coordination number, the spin magnetic moment decreases linearly from 3.8 μB to 0.2 μB, and the high spin content decreases linearly from 31% to 5%. Significantly, a volcanic curve between the spin states of Fe-based catalysts (Fe-NxPy) and oxygen reduction reaction (ORR) activity has been unequivocally established based on the thermodynamic results. Thus, the Fe-N3P1 catalyst with a 19% medium spin state experimentally exhibits the optimal reaction activity with a high half-wave potential of 0.92 V. These findings indicate that regulating electron spin moments through coordination engineering is a promising catalyst design strategy, providing important insights into spin catalysis.

Improving Glycerol Electrooxidation Performance on Nanocubic PtCo Catalysts.

As glycerol (GLY) has emerged as a highly functional and cheap platform molecule and as an abundant biodiesel production byproduct, possible conversion methods have been investigated. One of the promising approaches is the glycerol electrooxidation (GEOR) on noble metal-based catalysts. Although noble metals, especially Pt, are generally very stable at different pH and highly selective toward three-carbon (C3) products, their electrocatalytic performance can be further improved by morphology tuning and alloying with non-noble metals like Co. In the present study, cubic PtxCo100-x (x = 100, 80, and 60) nanoparticles were investigated in an alkaline medium at 20 and 40 °C. The effect of the composition and reaction conditions on the selectivity of the GEOR toward C3 products like lactate and glycerate was studied, and the reaction mechanism was discussed. The highest mass activity was found for Pt80Co20, although when the specific activity, glycerol conversion, and GEOR selectivity were compared, Pt60Co40 was the superior catalyst overall. In general, all catalysts, even those that are Co-rich, exhibited a high C3 product selectivity up to 95% at 0.67 V vs RHE. The low applied potential of 0.67 V vs RHE at 40 °C facilitated lactate formation with selectivity up to 72%. At the same time, the glycerate formation with a selectivity of up to 40%, as well as C-C bond cleavage, was more favored at 0.87 V vs RHE.

Unlocking the Electrocatalytic Behavior of Cu2MnS2 Nanoflake-Anchored rGO for the Oxygen Evolution Reaction in an Alkaline Medium.

A catalyst of the oxygen evolution reaction (OER) that is viable, affordable, and active for effective water-splitting applications is critical. A variety of electrocatalysts have been discovered to replace noble metal-based catalysts. Of these, transition metal-based sulfides are essential for incorporating carbonaceous materials to improve electrical conductivity, resulting in better electrocatalytic performance. Our study illustrates the synthesis of Cu2MnS2 (CMS) nanoflakes and their different rGO composites (10 to 40 wt %) via a hydrothermal technique for an effective water oxidation reaction. The X-ray diffraction pattern reveals that the prepared Cu2MnS2 nanoflakes exhibit a cubic crystal structure. The high-resolution scanning electron microscopy and the high resolution transmission electron microscopy images corroborate the formation of the nanoflake-like morphology of Cu2MnS2 with the strong interaction of rGO. The selected area electron diffraction analysis pattern reveals a polycrystalline nature. The Fourier transform infrared spectrum shows the existence of a metal sulfur vibrational band at 590 cm-1, and Raman analysis infers the presence of rGO. The X-ray photoelectron spectroscopy spectra reveal the oxidation states of the elements present in the samples. Using Brunauer-Emmett-Teller analysis, the surface area of CMS-20 is found to be 117.04 m2/g. The measured OER overpotentials using linear sweep volammetry and the values are 380, 370, 340, 376, and 400 mV at 10 mA/cm2 for CMS, CMS-10, CMS-20, CMS-30, and CMS-40, respectively, and the corresponding Tafel slope values are 179, 158, 149, 206, and 240 mV/decade, respectively. The electrochemical active surface area is estimated using cyclic voltammetry for all of the catalysts, where CMS-20 showed a larger surface area. Also, the same catalyst exhibits good stability for ∼24 h at a constant potential, which is confirmed via chronoamperometry. Thus, combining transition metal-based sulfides with carbonaceous materials indicates improved catalytic behavior for the preparation of high-performance OER electrocatalysts. Overall, the prepared CMS-20 performed as an efficient OER electrocatalyst and can be utilized for practical applications in energy conversion.

Cr-doped tri-metallic nano prism catalyst for efficient alkaline and seawater splitting

Electrochemical water splitting is one of the most promising methods for sustainable production of green hydrogen. The oxygen evolution reaction (OER) is a crucial step in the process of water splitting. However, it exhibits sluggish kinetics and requires a significant overpotential for functioning at reasonable reactionrates. The efficiency of the reaction can be enhanced by reducing the overpotential, lowering the energy barrier, and using an effective electrocatalyst. Transition metal-basedcatalysts are well studied for this purpose. Specially, nickel–cobalt (Ni-Co) based catalysts have been regarded as the best OER electrocatalysts. Therefore, several studies have been carried out to enhance the electrocatalytic efficiency of Ni-Co catalysts. While mixing other transition metals with Ni-Co is a straightforward and reliable method to improve the OER activity of Ni-Co catalysts, there is still a need for a thorough examination of the design of Ni-Co catalysts with various additional elements. Seawater electrolysis, which utilizes abundant water resources that constitute over 97% of the world’s water, is highly appealing for sustainable energy production. To achieve commercial feasibility, scientists are striving to solve challenges, such as corrosion resistance, highoverpotential, and the need for efficient and durable electrocatalysts.In this study, we fabricated a transition metal-based trimetallic catalyst (CNF), consisting of cobalt (Co), nickel (Ni), and iron (Fe). Furthermore, CNF was doped with chromium (Cr-doped CNF) and tested for the OER in alkaline freshwater and alkaline seawater. Our Cr-doped trimetallic CNF catalyst demonstrates exceptional performance in both seawater and freshwater, with overpotential of 320 mV and 280 mV at 10 mA cm−2 current density, making it a promising candidate for large-scale, sustainable hydrogen production.

P-Block Aluminum Single-Atom Catalyst for Electrocatalytic CO2 Reduction with High Intrinsic Activity.

Atomically dispersed transition metal sites on nitrogen-doped carbon catalysts hold great potential for the electrochemical CO2 reduction reaction (CO2RR) to CO due to their encouraging selectivity. However, their intrinsic activity is restricted by the hurdle of the high energy barrier of either *COOH formation or *CO desorption due to the scaling relationship. Herein, we discover a p-block aluminum single-atom catalyst (Al-NC) featuring an Al-N4 site that enables disentangling this hurdle, which endows a moderate reaction kinetic barrier for *COOH formation and *CO desorption, as validated by in situ attenuated total reflection infrared spectroscopy and theoretical simulations. As a result, the developed Al-NC shows a CO Faradaic efficiency (FECO) of up to 98.76% at -0.65 V vs RHE and an intrinsic catalytic turnover frequency of 3.60 s-1 at -0.99 V vs RHE, exceeding those of the state-of-the-art Ni-NC and Fe-NC counterparts. Moreover, it also delivers a partial CO current of 309 mA·cm-2 at 93.65% FECO and 605 mA at >85% FECO in a flow cell and membrane electrode assembly (MEA), respectively. Strikingly, when using low-concentration CO2 (30%) as the feedstock, this catalyst can still deliver a partial CO current of 240 mA at >80% FECO in the MEA. Considering the earth-abundant character of the Al element and the high intrinsic activity of the Al-NC catalyst, it is a promising alternative to today's transition metal-based single-atom catalysts.

Fine regulation of self-supporting metal phosphonates for improved overall water splitting

The exploration of high-performance water electrolysis catalysts is crucial for the development of hydrogen energy and the alleviation of increasingly serious environmental problems. Transition metal phosphonates are very promising electrocatalysts. In this work, a new nickel phosphonate has been synthesized and successfully developed into high-performance electrocatalyst through in-situ growth on nickel foam (NF), introduction of iron, and adjustment of Ni:Fe mole ratio. It is revealed that NiFe12 and NIFe13 exhibit the best OER (η10: 268 mV vs. RHE; Tafel slope: 54 mV dec−1) and HER (η10: 172 mV vs. RHE; Tafel slope: 77 mV dec−1) catalytic activity under optimized conditions, respectively, with fast reaction kinetics and long-term durability. The water electrolysis device assembled with them can drive a current density of 10 mA cm−2 at low voltage (1.68 V) with long-term durability, demonstrating promising application prospects. This work has important reference significance for the development of transition metal-based water electrolysis catalysts.

Synthetic Strategies for Adding Enantioselectivity to Metal-Based Solid Catalysts Using Cinchonidine As the Chiral Agent

Synthetic Strategies for Adding Enantioselectivity to Metal-Based Solid Catalysts Using Cinchonidine As the Chiral Agent

Excellent antibiotic degradation through PMS activation via bio derived Fe-Mn oxides with tunable defect concentration: Synergy between singlet oxygen oxidation and electron transfer

Regulating the defect sites and structural composition of metal-based metal catalysts is an effective strategy to improve the activity of activating PMS to degrade pollutants. Herein, bio derived Fe/Mn composite oxides (BFMO) rich in oxygen vacancy composed of crystalline manganese oxide coated with amorphous iron oxide was prepared through microbial mediation, and used for PMS activation in the degradation of tetracycline (TC). After 60 minutes reaction, the removal rate of TC achieved 92.4 %−98.8 % within wide pH range of 3–12. Besides, this system has outstanding anti-interference ability to common ions and humic acid (HA). The outstanding catalytic performance stemmed from the non-radical pathway for producing singlet oxygen (1O2) and electron transfer, facilitated by defect-rich polyvalent Mn and amorphous Fe species. Polyvalent Mn species accelerate the electron transfer process, and its surface defect structure further promotes the adsorption of pollutants on the surface of the materials. The redox cycle of Fe3+/Fe2+ was accelerate via electron-rich groups. This study explored the synergy triggered by microbe-mediated defect sites and structure-dependent, providing a design strategy for environmental remediation of PMS activated by Fe/Mn based bimetallic catalysts with strong resistance to environmental interference.

Engineering rare earth metal Ce-N coordination as catalyst for high redox kinetics in lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries are a key area of research in energy storage due to their high theoretical energy density, low cost, and environmental friendliness. However, the shuttle effect caused by lithium polysulfides (LiPSs) intermediates often results in poor cycling stability. Therefore, constructing rational cathode structures to achieve fast reaction kinetics in adsorbing and catalyzing LiPSs is the key to obtain high-performance Li-S batteries. Metallic single-atom catalysts (SACs), known for their 100 % atomic utilization rate and low cost, have demonstrated excellent catalytic activity and selectivity in the redox reactions of Li-S batteries, positioning them as one of the most promising catalysts in this field. Rare earth metallic SACs with versatile oxidation states, diverse coordination chemistry and environmentally friendly are rarely investigated in Li-S system. Herein, we fabricate a rare earth metal-based single-atom catalyst (CeSAs) supported on a three-dimensional porous N-doped carbon (3DCeSA-N-WS), and systematically study its performance in Li-S batteries. Benefitting from the atomic dispersion and versatile oxidation states (Ce3+/Ce4+), the 3DCeSA-N-WS demonstrates excellent performance in anchoring and catalyzing LiPSs, significantly enhancing the redox reaction kinetics. Consequently, the prepared sulfur cathode exhibits exceptional electrochemical performance, with a high initial specific discharge capacity of 1225 mAh g−1 at 0.2 C and a capacity retention of 76.1 % after 160 cycles. The assembled 100 mAh-level pouch cellmaintains a high specific discharge capacity of 877 mAh g−1 after 50 cycles at 0.5 C. This work provides new insights into the design of sulfur cathode catalysts, thereby contributing to the realization of high-performance Li-S batteries.

Atomically dispersed Ru on flower-like In2O3 to boost CO2 hydrogenation to methanol

Metal-based catalysts are prevalent in the CO2 hydrogenation to methanol owing to their remarkable catalytic activity. Herein, Ru/In2O3 catalysts with different morphologies obtained by doping Ru into In2O3 with irregular, rod-like, and flower-like morphologies are used for catalytic CO2 hydrogenation to methanol. Results indicate that the flower-like Ru/In2O3 (Ru/In2O3-F) exhibits higher catalytic performance than Ru/In2O3 with other morphologies, achieving a 12.9% CO2 conversion, 74.02% methanol selectivity, and 671.36 mgMeOH·h−1·gcat−1 methanol spatiotemporal yield. Furthermore, Ru/In2O3-F maintains its catalytic stability over 200 h at 5 MPa and 290 °C. The promotional effect mainly stems from the fact that electronic structure of Ru can be effectively adjusted by modulating the morphology of In2O3. The strong interaction between atomically dispersed Ru and In2O3-F enhances the structural stability of Ru, inhibiting the agglomeration of the catalyst during the reaction process. Furthermore, density-functional theory calculations reveal that highly dispersed Ru atoms not only perform efficient and rapid electronic gain and loss processes, facilitating the catalytic activation of H2 into H intermediates. It also enables the generated reactive H to rapidly overflow to the surrounding In sites to participate in CO2 reduction. These findings provide a theoretical basis for the development of high-performance catalysts for CO2 hydrogenation.

Enhancement in the performance of a vanadium-manganese redox flow battery using electrospun carbon metal-based electrode catalysts

This study investigates the performance of both a vanadium/manganese redox flow battery (V/Mn RFB) and an all-vanadium redox flow battery (VRFB), employing carbon metal fabrics (CMFs) prepared through electrospinning followed by carbonization. Noteworthy advancements are observed in both systems upon coupling CMFs with thermally treated graphite felt (GF) electrodes. Nearly doubled peak power density and 50 % higher capacity utilization over 150 charge/discharge cycles at 75 mA cm−2 are achieved for the V/Mn RFB with the incorporation of CMFs alongside graphite felt as catalysts. The VRFB demonstrates notable enhancements too, achieving approximately 200 cycles at a current density of 80 mA cm−2, with high efficiencies (85 %) and electrolyte utilization (79 %) when CMFs are used in combination with graphite felts. These advancements may facilitate pilot-scale testing and integration of the V/Mn RFB for the employment in the renewable energy storage sector and grid-balancing studies.

Noble metal-free tandem catalysis enables efficient upcycling plastic waste into liquid fuel components

The lack of effective approaches for upcycling waste plastic has led to severe environmental pollution and squandering of carbon resources. While hydrocracking macromolecular polyolefins over typical metal-zeolite catalyst produces high quality liquid fuel components, the limited activity of base metal and restricted accessibility of acid sites within microporous zeolite renders this process still not in practical scale. A tandem catalyst comprising Ni-WO3/Al2O3 and Beta zeolite was developed for consecutive hydrocracking polyolefins, achieving a yield of 86.2 % of primarily gasoline-jet ranged hydrocarbons (mainly C5-C16 and minor C16+) at 280 °C. The incorporation of tungsten species onto Ni/Al2O3 largely enhances the surface acidity and accelerates the primary cracking process that converts polyethylene (PE) into medium-sized intermediates, which would readily diffuse into the pore networks of Beta and undergo further cracking to yield desired liquid hydrocarbons. In addition, this tandem catalyst also promotes facile hydrocracking of consumer-grade plastic waste and maintains excellent stability over 5 recycling tests. The noble-metal-free catalyst achieves an impressive liquid formation rate of 5.74 g·gcat.−1·h−1, rivaling the noble metal-based catalyst and demonstrating high application prospects.

Tailored Metal-Based Catalysts: A New Platform for Targeted Anticancer Therapies.

Innovative strategies for targeted anticancer therapies have gained significant momentum, with metal complexes emerging as tunable catalysts for more effective and safer treatments. Rational design and engineering of metal complexes enable the development of tailored molecular structures optimized for precision oncology. The strategic incorporation of metal complex catalysts within combinatorial therapies amplifies their anticancer properties. This perspective highlights the advancements in synthetic strategies and rational design since 2019, showing how tailored metal catalysts are optimized by designing structures to release or in situ synthesize active drugs, leveraging the target-specific characteristics to develop more precise cancer therapies. This review explores metal-based catalysts, including those conjugated with biomolecules, nanostructures, and metal-organic frameworks (MOFs), highlighting their catalytic activity in biological environments and their in vitro/in vivo performance. To sum up, the potential of metal complexes as catalysts to reshape the landscape of anticancer therapies and foster novel avenues for therapeutic advancement is emphasized.

Low-temperature dechlorination methods for pyrolysis oil of municipal plastic waste

Pyrolysis oil produced from municipal plastic waste can be utilized as fuel and various valuable chemicals as an alternative to petroleum. However, pyrolysis oil usually contains a relatively high concentration of chlorinated compounds, obstructing its utilization in the chemical industry. The present research reveals that pyrolysis oil contains inorganic chlorine and organochlorine compounds, and differentiated approaches should be considered to remove Cl from covalent and ionic chlorine linkages. Transition metal-based ZSM-5 catalysts showed remarkable dechlorination performance via mild C-Cl cracking of 1-chlorooctane and 4-chlorotoluene at 180 °C or below. The neutralization method of mixing pyrolysis oil with an alkaline solution quickly eliminated ionic chlorine from inorganic chlorine compounds, reducing Cl concentrations by up to 70 % at temperature below 40 °C. Based on the different dechlorinating pathways, an ideal combination of these two methods was suggested to enhance chlorine removal efficiency from pyrolysis oil.

Direct construction of imidazoles via oxidative C(sp3)–H amination and annulation of aryethylamines by a Single-Atom cobalt catalyst

The development of reusable catalytic systems for achieving site-selective functionalization of C(sp3)-H bond remains a significant challenge. Herein, we designed a modified metal–organic framework (MOF)-derived N, P co-doped carbon supported single-atom cobalt catalyst, which was successfully applied in oxidative C(sp3)–H amination and cyclization of aryethylamines for construction of polysubstituted imidazoles. The advantages of the present method include: broad substrate scope, recyclable base metal catalyst, and naturally abundant O2 as green oxidant. The structural − activity relationship of the catalyst indicated that the atomically dispersed CoN3P1 is the active species responsible for the catalytic process. Furthermore, the synthesized imidazoles exhibited exceptional insecticidal activity against wheat pests, and may become lead molecules in the development of novel agricultural pesticide candidates, with significant application potential.

Hierarchical Superhydrophilic/Superaerophobic Ni3S2/VS2 Nanorod-Based Bifunctional Electrocatalyst Supported on Nickel Foam for Overall Urea Electrolysis.

The design and preparation of effective nonprecious metal-based catalysts for the urea oxidation reaction (UOR) coupled with the hydrogen evolution reaction (HER) are of great significance to solve both energy shortage and environmental pollution problems. In this study, a novel hierarchical superhydrophilic and superaerophobicity three-dimensional nanorod-like bifunctional catalyst with a heterostructure (Ni3S2/VS2) was prepared on nickel foam via a simple one-step hydrothermal method, serving as an excellent electrocatalyst for both UOR and HER. The formed heterostructure significantly alters the electronic structure, optimizing charge transfer and increasing the number of active sites, which enhances the electrocatalytic performance of Ni3S2/VS2. As a result, this catalyst requires an extremely low potential of 1.396 V at the current density of 100 mA cm-2 for UOR and only 164 mV overpotential at -10 mA cm-2 for HER. Notably, a constructed two-electrode electrolyzer system (Ni3S2/VS2∥Ni3S2/VS2) demonstrates extraordinary activity and long-term stability, achieving a current density of 10 mA cm-2 at a low cell voltage of 1.48 V, which is superior to majority of the reported catalysts. This work demonstrates that the formation of heterostructures can effectively enhance the catalytic activity of nanomaterials toward UOR and HER and provides a feasible strategy for fabricating highly efficient nonprecious metal overall urea electrocatalysts.

Exploration of cobalt-based spinel oxide nanocatalysts MCo2O4 (M = Mn, Fe, Co, Ni, Cu, Zn) for glucose electrochemical sensing: NiCo2O4 exhibits largest Faradaic current

In traditional glucose sensing, glucose undergoes an enzyme-catalyzed oxidation reaction (GOR) on the electrode, causing electron transfer and generating a Faradaic current, which allows for quantitative glucose concentration analysis by measuring the current. Replacing enzymes with transition metal-based catalysts for glucose electrochemical sensing is a promising approach. As an extension of the study of spinel oxide Co3O4 for glucose electrochemical sensing, a series of cobalt-based spinel oxide nanocatalysts, MCo2O4 (M = Mn, Fe, Co, Ni, Cu, Zn), were prepared and studied. Their electrocatalytic oxidation activities for 3 mM glucose in 0.1 M KOH electrolyte solution (pH = 13) at potentials of 0.5 ∼ 0.6 V (vs Hg/HgO) are in the order: NiCo2O4 > CuCo2O4 > MnCo2O4 > Co3O4 > FeCo2O4 > ZnCo2O4, the Faradic current by NiCo2O4 is more than three times that of Co3O4. When NiCo2O4 is loaded onto a carbon cloth electrode for glucose electrochemical sensing, it exhibits high linear sensitivity and stability. Furthermore, theoretical calculations revealed that the high electrocatalytic oxidation activity of NiCo2O4 for glucose is due to its effective reduction of the Gibbs free energy barrier for the desorption of intermediates to form glucose oxidation product. Finally, it is proposed that the electrocatalytic oxidation activities of MCo2O4 (M = Mn, Fe, Co, Ni, Cu, and Zn) towards glucose exhibit a “volcano plot” relationship with their d-band centers. This offers valuable guidance into using the d-band center as a descriptor to screen effective glucose electrocatalysts for glucose sensing and potentially other applications.

Electrocatalytic Conversion of CO2 to Formic Acid: A Journey from 3d-Transition Metal-Based Molecular Catalyst Design to Electrolyzer Assembly.

ConspectusElectrochemical CO2 reduction to obtain formate or formic acid is receiving significant attention as a method to combat the global warming crisis. Significant efforts have been devoted to the advancement of CO2 reduction techniques over the past few decades. This Account provides a unified discussion on various electrochemical methodologies for CO2 to formate conversion, with a particular focus on recent advancements in utilizing 3d-transition-metal-based molecular catalysts. This Account primarily focuses on understanding molecular functions and mechanisms under homogeneous conditions, which is essential for assessing the optimized reaction conditions for molecular catalysts. The unique architectural features of the formate dehydrogenase (FDH) enzyme provide insight into the key role of the surrounding protein scaffold in modulating the active site dynamics for stabilizing the key metal-bound CO2 intermediate. Additionally, the protein moiety also triggers a facile proton relay around the active site to drive electrocatalytic CO2 reduction forward. The fine-tuning of FDH machinery also ensures that the electrocatalytic CO2 reduction leads to the production of formic acid as the major yield without any other carbonaceous products, while limiting the competitive hydrogen evolution reaction. These lessons from the enzymes are key in designing biomimetic molecular catalysts, primarily based on multidentate ligand scaffolds containing peripheral proton relays. The subtle modifications of the ligand framework ensure the favored production of formic acid following electrocatalytic CO2 reduction in the solution phase. Next, the molecular catalysts are required to be mounted on robust electroactive surfaces to develop their corresponding heterogeneous versions. The surface-immobilization provides an edge to the molecular electrocatalysts as their reactivity can be scaled up with improved durability for long-term electrocatalysis. Despite challenges in developing high-performance, selective catalysts for the CO2 to formic acid transformation, significant progress is being made with the tactical use of graphene and carbon nanotube-based materials. To date, the majority of the research activity stops here, as the development of an operational CO2 to formic acid converting electrolyzer prototype still remains in its infancy. To elaborate on the potential future steps, this Account covers the design, scaling parameters, and existing challenges of assembling large-scale electrolyzers. A short glimpse at the utilization of electrolyzers for industrial-scale CO2 reduction is also provided here. The proper evaluation of the surface-immobilized electrocatalysts assembled in an electrolyzer is a key step for gauging their potential for practical viability. Here, the key electrochemical parameters and their expected values for industrial-scale electrolyzers have been discussed. Finally, the techno-economic aspects of the electrolyzer setup are summarized, completing the journey from tactical design of molecular catalysts to their appropriate application in a commercially viable electrolyzer setup for CO2 to formate electroreduction. Thus, this Account portrays the complete story of the evolution of a molecular catalyst to its sustainable application in CO2 utilization.

Nanoarchitectonics of vanadium nanoparticles decorated mesoporous carbon nitride in photocatalytic systems: A study on ethylbenzene oxidation reaction

In this work, we have described the synthesis of vanadium (V) nanoparticles (NPs) anchored on mesoporous graphitic carbon nitride (V@mpg-C3N4) and their uses in photocatalytic ethylbenzene oxidation to the respective acetophenones. The mpg-C3N4 serves as the support for the decoration of V NPs, through a simple impregnation method. Various advanced techniques, such as XRD, UV–vis spectrometry, HRTEM, HAADF-STEM, AC-STEM, elemental mapping, and BET surface area analysis, were employed for the characterization of V@mpg-C3N4. The detailed characterization studies reveal that the V@mpg-C3N4 catalyst has a medium band gap (2.78 eV), a high surface area (76.7 m2g−1), and a mesoporous nature. The V@mpg-C3N4 photocatalysts demonstrated excellent performance in the light-assisted oxidation of ethylbenzene, achieving over 99 % conversion and selectivity for acetophenone in an environmentally friendly solvent (water) using a domestic light source (50 W white light). This developed synthesis strategy will be useful for synthesizing various noble and non-noble metal-based catalysts and their applications in organic transformation and environmental remediation.

Photocatalytic Acetylene Hydrochlorination by Pairing Proton Reduction and Chlorine Oxidation over g-C3N4/BiOCl Catalysts.

Acetylene hydrochlorination is a vital industrial process for the manufacture of vinyl chloride monomer (VCM). Current thermocatalytic acetylene hydrochlorination requires toxic mercury-based or costly noble metal-based catalysts, high temperatures (≥180 °C) and excessive gaseous HCl. Here, we report a room-temperature photocatalytic acetylene hydrochlorination strategy involving concurrent coupling of electron-driven proton reduction (*H) and hole-driven chloride oxidation (*Cl) on photocatalyst surfaces. Under simulated solar light illumination, the developed noble-metal-free g-C3N4/BiOCl photocatalysts show a considerably high VCM production rate of 1198.6 μmol g-1 h-1 and a high VCM selectivity of 95% in a 0.1 M HCl aqueous solution. Even in chloride-rich natural seawater and acidified natural seawater, the VCM production rates of g-C3N4/BiOCl photocatalysts are up to 170.3 μmol g-1 h-1 with a VCM selectivity of 80.4% and 1247.7 μmol g-1 h-1 with a VCM selectivity of 94.7%, respectively. Moreover, with sunlight irradiation and acidified natural seawater, the g-C3N4/BiOCl photocatalysts in a large-scale photosystem retain outstanding acetylene hydrochlorination performance over 10 days of operation. The radical scavenging, in situ photochemical Fourier transform infrared spectroscopy, theoretical simulations, and control experiments reveal that active *Cl and *H play key roles in photocatalytic acetylene hydrochlorination via a possible reaction pathway of C2H2 → *C2H2 → *C2H2Cl → *C2H3Cl → C2H3Cl. With respect to sustainability and low cost, this photocatalytic acetylene hydrochlorination offers excellent advantages over conventional thermocatalytic hydrochlorination technologies.