Superior Catalytic Performance Research Articles

Insights into the Distinct Behaviors between Bifunctional and Binary Organoborane Catalysts through Terpolymerization of Epoxide, CO2, and Anhydride

AbstractAlkyl borane compounds‐mediated polymerizations have expanded to Lewis pair polymerization, free radical polymerization, ionic ring‐opening polymerization, and polyhomologation. The bifunctional organoborane catalysts that contain the Lewis acid and ammonium or phosphonium salt in one molecule have demonstrated superior catalytic performance for ring‐opening polymerization of epoxides and ring‐opening copolymerization of epoxides and CO2 than their two‐component analogues, i.e., the blend of organoborane and ammonium or phosphonium salt. To explore the origin of the differences of the one‐component and two‐component organoborane catalysts, here we conducted a systematic investigation on the catalytic performances of these two kinds of organoborane catalysts via terpolymerization of epoxide, carbon dioxide and anhydride. The resultant terpolymers produced independently by bifunctional and binary organoborane catalyst exhibited distinct microstructures, where a series of gradient polyester‐polycarbonate terpolymers with varying polyester content were afforded using the bifunctional catalyst, while tapering diblock terpolymers were obtained using the binary system. The bifunctional catalyst enhances the competitiveness of CO2 insertion than anhydride, which leads to the premature incorporation of CO2 into the polymer chains and ultimately results in the formation of gradient terpolymers. DFT calculations revealed the role of electrostatic interaction and charge distribution caused by intramolecular synergistic effect for bifunctional organoborane catalyst.

Quasi-Homogeneous Photocatalysis in Ultrastiff Microporous Polymer Aerogels.

The development of efficient and low-cost catalysts is essential for photocatalysis; however, the intrinsically low photocatalytic efficiency as well as the difficulty in using and recycling photocatalysts in powder morphology greatly limit their practical performance. Herein, we describe quasi-homogeneous photocatalysis to overcome these two limitations by constructing ultrastiff, hierarchically porous, and photoactive aerogels of conjugated microporous polymers (CMPs). The CMP aerogels exhibit low density but high stiffness beyond 105 m2 s-2, outperforming most low-density materials. Extraordinary stiffness ensures their use as robust scaffolds for scaled photocatalysis and recycling without damage at the macroscopic level. A challenging but desirable reaction for direct deaminative borylation is demonstrated using CMP aerogel-based quasi-homogeneous photocatalysis with gram-scale productivity and record-high efficiency under ambient conditions. Combined terahertz and transient absorption spectroscopic studies unveil the generation of high-mobility free carriers and long-lived excitonic species in the CMP aerogels, underlying the observed superior catalytic performance.

La-Co-Mn perovskite (LCMO) for NO and Hg0 oxidation: Experimental and DFT investigations of adsorption processes

To achieve superior catalytic performance, the development of plausible regulation of pure perovskite structure is necessary, which has become a hot research topic. In this study, manganese (Mn) ions were employed to dope cobalt (Co) ions at the B-site of LaCoO3, yielding a series of LaCo1-xMnxO3 (x = 0.1–0.5) perovskite (LCMO). The oxidation activity of NO and Hg0 was conducted, evaluating the effect of Mn-doping. The results indicated a minor change in NO oxidation activity and a significant enhancement in Hg0 oxidation, reaching above 92% at 100°C–300°C for LCMO. Structural characterization revealed a gradual transition in the phase structure of LCMO from the R-3C diamond phase to the Pm-3m cubic phase with increasing Mn doping. Furthermore, electronegativity properties of LCMO evolved with Co ions at the B-site exhibiting a preference for generating Co2+ over the more active Co3+. Finally, DFT calculations were conducted to analyze the adsorption energies of NO and Hg0 at different active sites on the surfaces of LaCoO3 (110) and Mn-LaCoO3 (110). The results indicated that Mn doping increased the active site amounts and strengthened the adsorption energy of Hg0 on the Mn-LaCoO3 (110) surface. However, the adsorption energy of NO remained largely unchanged, validating the oxidation results. This study offered insights for selecting B-site ions to adjust the perovskite structure of excellent performance, facilitating its industrial application.

Cyclo[16]carbon through the lens of density functional theory: Role of impurity decoration in hydrogen evolution reaction

The increasing global demand for sustainable energy sources has intensified the search for cost-effective catalysts in the hydrogen evolution reaction (HER). Single-atom catalysts (SACs) supported on suitable substrates have emerged as promising alternatives. In this study, we investigate the utilization of cyclo[16]carbon (C16 nanocluster) as a support for second-row transition metals (TMs) based SACs. The exploration focuses on analyzing the geometry, electronic properties, stability, and catalytic performance of TM@C16 SACs in the context of HER. Notably, highly negative binding energy values, structural modifications, and altered dipole moments collectively affirm the strong binding between the TMs and the C16 nanocluster. The incorporation of TMs onto the C16 nanocluster substantially enhances the conductivity of the latter. Studied SACs primarily showed H2 evolution via Volmer-Heyrovsky mechanisms. Notably, Pd@C16 and Rh@C16 displayed superior catalytic performance, with ΔGHV values of −0.007 eV and 0.05 eV, respectively. The determination of the exchange current via a volcano plot as a function of Gibbs free energy for hydrogen evolution over these designed SACs further validates their efficacy. Our findings establish Pd@C16 and Rh@C16 as highly stable and efficient SACs for the HER, underscoring their potential in advancing sustainable energy technologies.

Ultrasound-Triggered Piezoelectric Catalysis of Zinc Oxide@Glucose Derived Carbon Spheres for the Treatment of MRSA Infected Osteomyelitis.

Currently, methicillin-resistant Staphylococcus aureus (MRSA)-induced osteomyelitis is a clinically life-threatening disease, however, long-term antibiotic treatment can lead to bacterial resistance, posing a huge challenge to treatment and public health. In this study, glucose-derived carbon spheres loaded with zinc oxide (ZnO@HTCS) are successfully constructed. This composite demonstrates the robust ability to generate reactive oxygen species (ROS) under ultrasound (US) irradiation, eradicating 99.788% ± 0.087% of MRSA within 15min and effectively treating MRSA-induced osteomyelitis infection. Piezoelectric force microscopy tests and finite element method simulations reveal that the ZnO@HTCS composite exhibits superior piezoelectric catalytic performance compared to pure ZnO, making it a unique piezoelectric sonosensitizer. Density functional theory calculations reveal that the formation of a Mott-Schottky heterojunction and an internal piezoelectric field within the interface accelerates the electron transfer and the separation of electron-hole pairs. Concurrently, surface vacancies of the composite enable the adsorption of a greater amount of oxygen, enhancing the piezoelectric catalytic effect and generating a substantial quantity of ROS. This work not only presents a promising approach for augmenting piezoelectric catalysis through construction of a Schottky heterojunction interface but also provides a novel, efficient therapeutic strategy for treating osteomyelitis.

Zeolite-Templated Carbons Supported Rh and Ru Electrocatalysts for Highly Active Hydrogen Evolution Reaction.

Here, we report the systematical synthesis of zeolite-templated carbon (ZTC) supported Ru and Rh mono- or bi-metallic electrocatalysts towards hydrogen evolution reaction (HER). The zeolite A or ZSM5 derived ZTC supports and metal sites were adjusted, and all electrocatalysts outperformed the commercial Pt/C electrocatalyst for HER performance. In particular, the RhRu/(ZTC/ZSM5) sample exhibited superior catalytic performance with the overpotential of 24.8 mV@10 mA·cm-2, and outstanding stability with 1 mV drop after 20000 cyclic voltammetry circles. This work offers a simple impregnation method for the synthesis of highly performed HER electrocatalysts supported on porous carbon.

Effect of support structure of Pt/silicaite-1 catalyst on non-thermal plasma (NTP) assisted chlorobenzene degradation and PCDD/Fs formation

Development of efficient catalysts for non-thermal plasma (NTP) assisted catalysis to mitigate the formation of harmful by-products is a significant challenge in the degradation of chlorinated volatile organic compounds (Cl–VOCs). In this study, catalytically active Pt nanoparticles supported on non-porous SiO2 and silicalite-1 zeolites (S1) with different pore structure were comparatively investigated for catalytic chlorobenzene degradation under NTP condition. It was shown that the pore structure could significantly impact the metal size and metal dispersion rate. Pt supported on modified S1 hierarchical meso-micro-porous silicalite-1 (Pt/D-S1) exhibited the smallest particle size (∼6.19 nm) and the highest dispersion rate (∼1.87). Additionally, Pt/D-S1 demonstrated superior catalytic performance compared to the other catalysts, achieving the highest chlorobenzene conversion and COx selectivity at about 80% and 75%, respectively. Furthermore, the pore structure also affected the formation of by-products according to the findings from GC-MS analysis. Pt/SiO2 generated a total of 18 different species of organic compounds, whereas only 12 species of organic by-products were identified in the Pt/D-S1 system (e.g. polychlorinated compounds like 3,4 dichlorophenol were exclusively identified in Pt/SiO2). Moreover, dioxin-like polychlorinated biphenyl and other chlorinated organic compounds, which have potential to form highly toxic dioxins, were detected in the catalysts. HRGC-HRMS confirmed and quantified the 17 different dioxin/furans formed on Pt/SiO2 (25,100 ng TEQ kg−1), Pt/S1 (515 ng TEQ kg−1) and Pt/D-S1 (367 ng TEQ kg−1). The correlation between synthesis-structure-performance in this study provides insights into the design of catalysts for deep oxidation of Cl–VOCs in NTP system.

Completely Inorganic Deep Eutectic Solvents for Efficient and Recyclable Liquid-Liquid Interface Catalysis.

Organic acid-based deep eutectic solvents (DESs) as catalysts always suffer from weak stability and low recyclability due to the accumulation of organic oxidative products in the DES phase. Herein, a completely inorganic deep eutectic solvent (IDES) ZnCl2/PA with zinc chloride (ZnCl2) and phosphoric acid (PA) as precursors is constructed to realize liquid-liquid interface catalysis for desulfurization of fuel and product self-separation for the first time. Owing to the inorganic nature, the organic oxidative products are accumulated at the interface between the IDES and fuel rather than the IDES phase. With this unique feature, the IDES can be reused for at least 15 times without any further treatment in oxidative desulfurization process, showing a state-of-the-art cycle-regeneration stability. Moreover, compared with the reported organic DESs, the IDES also reveals more attractive catalytic oxidative desulfurization performance. Experimental and theoretical studies indicate that the strong coordination Zn···O═P and the strong adsorption energy between IDES and sulfides enhance the activation of H2O2 to reactive oxygen species, leading to the superior catalytic performance in oxidative desulfurization of fuel.

Single-atom Al precisely modulate the strain of Pt3Co intermetallic for superior oxygen catalytic performance

Precisely controlling the strain of Pt-based intermetallic to ensure high performance and stability is a massive task for sustainable proton-exchange-membrane-fuel-cells. Herein, the Al single-atom was trapped into the L12-Pt3Co intermetallic core to precisely tailor the strain state on the Pt-skin for fast oxygen reduction reaction kinetics. Theoretical calculations firstly predicted that only tailored tension can accelerate the protonation of O2 on L12-Pt3Co@Pt without creating an additional energy barrier for subsequent oxygen-containing intermediates desorption. Experimentally, Al single-atom confined in the L12-Pt3Co lattice by substituting partial Co occupancy, imposing tailored ∼ 0.2 % tension on Pt-skin compared to the L12-Pt3Co. L12-Al-Pt3Co@Pt/C exhibits enhanced mass activity which is ten-time improvement over commercial Pt/C. More significantly, XAS and DFT results reveal that the Al single-atom can strengthen the Pt-Co bonding, enhancing the stability of L12-Al-Pt3Co@Pt/C in oxygen reduction. This work provides an avenue to design the strain by single-atom for sustainable energy conversion technologies.

Facile Preparation of Stable NiII‐ and CoII‐tetraaminophthalocyanine Electropolymers for Highly Efficient Heterogeneous Carbon Dioxide Reduction

This study focused on preparation of stable polymer films of NiII‐ and CoII‐tetraaminophthalocyanines, p‐NiTAPc and p‐CoTAPc, respectively, for highly efficient heterogeneous electrochemical carbon dioxide (CO2) reduction in a flow electrolysis cell. Major development represented in this work was fabrication of p‐NiTAPc and p‐CoTAPc films via electropolymerization of their corresponding monomers on carbon‐based substrates without using binder or conducting additive materials to obtain efficient gas diffusion electrodes (GDEs) for scalable, productive and selective CO2‐to‐CO conversion. The target polymers were characterized by UV‐visible spectrophotometry, attenuated total reflection‐Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X‐ray spectroscopy and cyclic voltammetry. According to controlled potential electrolysis and gas chromatography, p‐NiTAPc‐catalyzed CO2 reduction at –0.99V vs. reversible hydrogen electrode (RHE) gave 953 mL of CO in a period of 16 hours with current density and Faradaic efficiency (FE) of 109±1 mA·cm‐2 and 99±2%, respectively. A p‐CoTAPc‐modified GDE exhibited superior catalytic performance to the case of p‐NiTAPc in terms of catalyst stability and CO productivity by performing the continuous CO2 reduction at the potential of –1.10 V vs. RHE for up to 41 hours and affording almost 3 times higher amount of CO with the current density of 161±5 mA/cm2 and 95±2% FE.

Cooperation between single atom catalyst and support to promote nitrogen electroreduction to ammonia: A theoretical insight

The co-catalysis between single atom catalyst (SAC) and its support has recently emerged as a promising strategy to synergistically boost the catalytic activity of some complex electrochemical reactions, encompassing multiple intermediates and pathways. Herein, we utilized defective BC3 monolayer-supported SACs as a prototype to investigate the cooperative effects of SACs and their support on the catalytic performance of the nitrogen reduction reaction (NRR) for ammonia (NH3) production. The results showed that these SACs can be firmly stabilized on these defective BC3 supports with high stability against aggregation. Furthermore, co-activation of the inert N2 reactant was observed in certain embedded SACs and their neighboring B atoms on the certain BC3 sheets due to the noticeable charge transfer and significant N–N bond elongation. Our high-throughput screening revealed that the Mo/DVCC and W/DVCC exhibit superior NRR catalytic performance, characterized by a low limiting potential of −0.33 and −0.43V, respectively, which can be further increased under acid conditions based on the constant potential method. Moreover, varying NRR catalytic activities can be attributed to the differences in the valence state of active sites. Remarkably, further microkinetic modeling analysis displayed that the turnover frequency of N2–to–NH3 conversion on Mo/DVCC is as large as 1.20 × 10−3 s−1 site−1 at 700 K and 100 bar, thus guaranteeing its ultra-fast reaction rate. Our results not only suggest promising advanced electrocatalysts for NRR, but also offered an effective avenue to regulate the electrocatalytic performance via the co-catalytic metal–support interactions.

Three-dimensional crosslinked structure assembled by novel elemental iodine doped Nb2O5 ultrathin nanosheets for exceptional visible-light photocatalytic performance

The application of Nb2O5 in photocatalysis has sparked interest due to its potent oxidation capabilities and eco-friendly properties. However, challenges such as poor visible light response, limited reactive active sites and rapid charge recombination still hinder its practical use. Herein, a novel approach introduces elemental I-doped Nb2O5 (INO) catalyst with a three-dimensional crosslinked structure formed by ultrathin nanosheets, for the first time. This pioneering approach results in the INO catalyst with a high specific surface area (98.51 m2 g−1), abundant active sites, and enhanced visible light absorption. The dispersion of elemental I within the Nb2O5 lattice promotes the presence of delocalized electrons and improves charge carrier mobility, leading to superior catalytic performance for the degradation of diclofenac (DCF). During a 75-min period, the degradation efficiency of INO catalyst to diclofenac was found to reach 91.5 %, with a corresponding rate constant of 35.0 × 10−3 min−1. Furthermore, the study investigates the DCF degradation pathway and the toxicity changes in its byproducts. This innovative research opens new avenues for enhancing the visible light catalytic activity of Nb2O5 catalysts.

The dual single-atom in and P co-promoters boost dimethyldichlorosilane production in the Rochow-Müller reaction

Investigating novel promoters and comprehending their roles is an important yet difficult task. In this study, we have introduced dual main-group single-atom In and P as co-promoters into the CuO surface lattice (In-P/CuO) via a straightforward hydrothermal CuO synthesis followed by impregnation. The In-P/CuO catalyst showed superior catalytic performance in dimethyldichlorosilane selectivity and yield to that of the pristine CuO and CuO with a single promoter in the important industrial Rochow-Müller reaction. The combination of thorough experimental characterization and density functional theory calculations reveals that the electron interaction between dual In and P promoters could optimize the local electronic structure of CuO and facilitate MeCl dissociation on the CuO surface, accelerating the transformation of CuO to Cu2O, then CuCl, and eventually the active phase Cu3Si and thereby enhancing overall activity. This work examines the synergistic interactions between dual main-group single-atom promoters in catalysts, offering a proven method for designing highly efficient catalysts.

Layered double oxide (CoAl-LDO) catalysis for enhanced ozonation of methyl orange: Performance assessment and mechanistic insights

In this study, we report the successful synthesis of a novel layered double oxide (CoAl-LDO) ozone catalyst through co-precipitation and high-temperature calcination method, utilizing layered double hydroxide (CoAl-LDH) as an uncalcined intermediate product. The synthesized CoAl-LDO exhibits a thinner and more curved plate-like morphology with well-developed porous structures, demonstrating richer content of active oxygen species and enhanced oxygen migration ability. Notably, the CoAl-LDO catalyst demonstrates superior catalytic performance compared to conventional catalysts and ozone alone systems. Utilizing methyl orange (MO) as the target pollutant, CoAl-LDO catalyzed ozonation achieved an impressive removal rate of 88.27 % within 10 min, surpassing the performance of CoAl-LDH (61.84 %), Co3O4 (57.71 %), and O3 alone systems (47.71 %). Moreover, the CoAl-LDO catalyst exhibited excellent stability and reusability, maintaining a removal rate above 72.13 % over four consecutive cycles. In addition, we propose a novel reaction mechanism for the catalytic ozonation based on the interconversion of Co2+ and Co3+ during the reaction process to generate oxygen vacancies (OV), which in turn react with water molecules and ozone molecules to produce ROS (especially O2−). These findings provide unique perspectives for the precise design and rational application of ozone catalysts.

Enhanced low-temperature activity of Mn-based catalysts for NH3 selective catalytic reduction of NO through CE-modulated redox and TiO2 shell construction

Manganese-based catalysts presented great challenges for the wide operating window in the selective catalytic reduction of NOx with NH3 (NH3-SCR). Aiming at enhancement of the SCR performance, a series of MnCeOx (MnyCe1) and MnxCe1@TiO2 catalysts were prepared. Impressively, the Mn1Ce1 catalyst exhibited excellent low-temperature activity, achieving over 80 % conversion of NO within the temperature range of 85–350 °C, but the N2 selectivity decreased with the increasing temperature. Upon coating a TiO2 shell, the temperature window with N2 selectivity exceeding 80 % was significantly widened to 85–350 °C since the weak redox ability limited the NH3 oxidation to undesired N2O. High surface area, together with abundant acid sites and chemical adsorbed oxygen that formed via the interaction between Mn4+/Mn3+, Ce4+/Ce3+ and Ti4+/Ti3+, contributed to the superior catalytic performance of MnxCe1@TiO2. In addition, through in situ DRIFTS analysis, both Eley-Rideal and Langmuir-Hinshelwood reaction routes were observed. This work would provide an efficient and low-cost strategy for preparing Mn-based catalysts with excellent low-temperature activity for NOx removal.

Synergistic catalysis effect of micro-mesoscopic channel for enhanced methyl oleate catalytic cracking to BTX: A molecular simulation study

The hierarchical ZSM-5 zeolite exhibits superior catalytic performance for methyl oleate catalytic cracking to BTX, while the promotion mechanism at the molecular level is still unclear. Herein, the adsorption and diffusion behaviors of reaction species in hierarchical ZSM-5 zeolite, including methyl oleate, C3H6, C4H8 and BTX, were theoretically investigated by Monte Carlo combined with Molecular Dynamics simulation. It is found that the introduction of mesopores exposes the strong adsorption sites (Brønsted acid) without a confinement effect, thereby promoting the adsorption and cracking of methyl oleate. Moreover, the as-formed C3H6 and C4H8 rapidly transfer from mesopore into micropore, enhancing the aromatization reaction to form BTX. Finally, thanks to the adjacent mesopore providing sufficient space for molecule rotation, the desired BTX products easily desorbs from the micropore. Such synergistic catalysis effect of micro-mesoscopic channel increases the BTX yield by decreasing the diffusion coefficient of C3H6 and C4H8 from 13.2 × 10-9 m2/s on the traditional to 6.4 × 10-9 m2/s on the hierarchical ZSM-5. We anticipate that this work could enrich our understanding of the microcosmic mechanism of hierarchical zeolites for prolific aromatics.

Against catalyst deactivation during toluene oxidation on CuCeOx in flue gas: High oxidation efficiency and rapid oxidation pathway

The removal of volatile organic compounds (VOCs) from flue gas by a tightly coupled catalytic oxidation process in the NH3-SCR unit is a cost-effective approach. A CuCeOx bimetallic mixed oxide catalyst prepared by the co-precipitation method has demonstrated the ability to completely convert toluene at 350 ℃ under simulated flue gas conditions. Cu oxide is considered as the main active site for toluene oxidation, and the introduction of Ce induced a synergistic effect which enhanced the surface adsorbed oxygen and oxidation performance. The CuCeOx catalyst was found to outperform commercial VOC catalysts (Pt/Al2O3) and SCR catalysts (V2O5-WO3/TiO2) under the influence of different flue gas components. The negative effect of the flue gas on CuCeOx almost diminished at 350 ℃. The mechanism study showed that toluene on CuCeOx underwent a rapid oxidation pathway, thereby avoiding the potential interaction between intermediates and flue gas components. The superior catalytic performance of CuCeOx in the simulated flue gas conditions were attributed to the higher toluene adsorption efficiency and weaker adsorption towards the flue gas components.

Bimetallic PtZn nanoparticles anchored in high-silica SSZ-13 zeolite for efficient propane dehydrogenation

Direct dehydrogenation of propane to propylene (PDH) is a promising route to meet the ever-growing global propylene demand, but the industrial Pt-based catalysts usually suffer from serious deactivation derived from coke deposition and sintering under harsh reaction conditions. In this work, PtZn bimetallic nanoparticles encapsulated into high-silica SSZ-13 zeolites (PtZn@SSZ-13) were synthesized via a facile ligand-protected interzeolite transformation strategy. In a PDH reaction, the synthesized 0.5Pt3Zn@SSZ-13 catalyst exhibits superior catalytic performance with a propane conversion of 23.7% and a propylene selectivity of 96.8%, which is significantly better than that of PtZn supported on high-silica SSZ-13 (0.5Pt3Zn/SSZ-13). Particularly, the high catalytic activity of this catalyst can be kept during three successive oxidation–reduction cycles. Detailed characterizations including HAADF-STEM, XPS, UV–Vis, H2-TPR reveal that the remarkable improvement of PDH performance is attributed to the PtZn synergistic effect as well as the confinement of SSZ-13 zeolites. The DFT calculations and microkinetic simulations also evidenced that the Pt particles anchored on the Zn-doped SSZ-13 zeolite pore framework possessed obviously higher propane dehydrogenation activity, whereas the anti-coking ability of 0.5Pt3Zn@SSZ-13 was also stronger than Pt (111) surface, demonstrating the superior performance of 0.5Pt3Zn@SSZ-13.

Revealing Hydrogen Spillover on 1T/2H MoS2 Heterostructures for an Enhanced Hydrogen Evolution Reaction by Scanning Electrochemical Microscopy.

The in situ characterization of the heterostructure active sites during the hydrogen evolution reaction (HER) process and the direct elucidation of the corresponding catalytic structure-activity relationships are essential for understanding the catalytic mechanism and designing catalysts with optimized activity. Hence, exploring the underlying reasons behind the exceptional catalytic performance necessitates a detailed analysis. Herein, we employed scanning electrochemical microscopy (SECM) to in situ image the topography and local electrocatalytic activity of 1T/2H MoS2 heterostructures on mixed-phase molybdenum disulfide (MoS2) with 20 nm spatial resolution. Our measurements provide direct data about HER activity, enabling us to differentiate the superior catalytic performance of 1T/2H MoS2 heterostructures compared to other active sites on the MoS2 surface. Combining this spatially resolved electrochemical information with density functional theory calculations and numerical simulations enables us to reveal the existence of hydrogen spillover from the 1T MoS2 surface to 1T/2H MoS2 heterostructures. Furthermore, it has been verified that hydrogen spillover can significantly enhance the electrocatalytic activity of the heterostructures, in addition to its strong electronic interaction. This study not only contributes to the future investigation of electrochemical processes at nanoscale active sites on structurally complex electrocatalysts but also provides new design strategies for improving the catalytic activity of 2D electrocatalysts.

NiCuAg: An electrochemically-synthesised trimetallic stack for CO2 reduction

Electrochemical CO2 reduction is a promising technique for the production of desirable hydrocarbons without the need to resort to fossil resources. However, high overpotentials and poor selectivity remain a challenge for CO2 electro-reduction, especially for deep reduction by more than two electrons. One apparently attractive approach for breaking the scaling relations caused by simultaneous CO2 reduction pathways and for achieving deeper reduction is the use of multi-metallic electrodes, where several promising metal catalysts are present in close proximity. Herein, noting the activity shown by Ni, Cu and Ag for CO2 electroreduction when used individually, we set out to synthesise a tri-metallic “stack” catalyst, NiCuAg, and then to test this for electrochemical CO2 reduction. The stack architecture was successfully generated and the trimetallic NiCuAg system did show improved Faradaic efficiency for the reduction of CO2 to formic acid when compared to the bare Ni and bimetallic NiCu controls under some select conditions. However, the two-layer NiCu stack and bare Ni exhibited consistently higher Faradaic efficiencies than NiCuAg for deeper CO2 electroreduction to methanol and ethanol, indicating that the combination of three individually promising metals does not necessarily translate into superior catalytic performance for deep carbon dioxide reduction. [Display omitted]