The electrochemical CO2 reduction reaction (CO2RR) presents a promising approach for producing valuable chemicals and fuels, offering a dual benefit in terms of environmental preservation and the efficient utilization of carbon resources.  In this work, we proposed a stepwise electrodeposition method to prepare Cu-Pb bimetallic heterojunction catalyst on polyaniline-modified carbon paper  (PANI-CuPb-x), where x is the electrodeposition times(min).  Among the studied catalysts, the electrode electrodeposited for 2 min (PANI-CuPb-2) exhibited a remarkable performance during the electrocatalysis CO2 to multicarbon (C2+) products process, achieving a Faraday efficiency (FE) of 81.46 % and a partial current density of 15.41 mA cm-2 at −1.2 V (vs. RHE) in an H-type cell. Detailed study demonstrated that introducing Pb could effectively improve the formation of COOH*inhibite hydrogen evolution reaction (HER). Furthermore, the heterojunction structure in the catalysts facilitated C-C coupling of the generated C1 intermediate species, which enhanced CO2 to C2+ reaction.

Autocatalytic reactions were proposed to play a key role at the beginning of life starting from the first reduction of CO2 to formate, acetate and C1-C4 hydrocarbons. In carbon capture and utilization (CCU) processes, the same reactions were demonstrated to be autocatalytic and, in some cases, promoted by catalysts of the same composition. Through evolution, CO2 reduction then turned into complex autocatalytic networks such as photosynthesis, where CCU chemists found inspiration for the development of more advanced systems for the synthesis of value-added chemicals. Less evolved systems than photosynthesis, however, may be easier to emulate and provide valuable inspiration into CO2 reduction chemistry for CCU. Other manmade systems were also demonstrated to be autocatalytic demonstrating that CO2 reactions and autocatalysis are closely connected. In this concept article, the relationship between natural, artificial and bio-inspired autocatalytic CO2 reduction processes is summarized and discussed. The accomplishments resulting from the integration of autocatalysis and CCU strategies, along with their inherent benefits and future prospectives are also outlined.

Partial oxidation of furanic biomass derivatives such as furfural is of interest for the sustainable production of chemicals including furoic acid, maleic acid, and 2,5-furandicarboxylic acid (FDCA). The oxidative bulk electrolysis of furfural is here investigated on platinum electrodes in acidic media. The effects of potential, concentration, pH, and supporting anion are studied, and selectivity trends are coupled with attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) to illuminate adsorbate structures that influence the catalysis. Increasing potential is found to shift selectivity from primarily C5 products to C4 products, coincident with oxidation of the Pt surface. Selectivity changes are also observed moving from pH 1 to pH 4, with an increase in C5 products at higher pH. Changing from the weakly adsorbing perchlorate anion to the specifically-adsorbing phosphate anion results in a number of changes that manifest differently depending on potential and pH. Selectivity to furoic acid is found to be highest above the pKa of phosphoric acid due to the strongly adsorbed phosphate ions suppressing flat-lying configurations of furfural that lead to C-C cleavage. These results point toward opportunities to use electrolyte engineering to tune selectivity and optimize surface conditions to disfavor binding of inhibitory products.

The structural evolution of CeO₂ in CeO₂−CuO catalyst was captured by in situ technique. Under reductive conditions, CeO₂ was exposed to the catalyst surface to form an inverse CeO_x/Cu interface with a high WGS activity. After the removing of the reductive condition, CeO₂ in the catalyst will undergo a surface reconstruction, which is manifested as oxygen migration and oxidation of Cu.

Abstract

The oxides and active metals at the interface synergistically activate reactants and thus promote the reaction, but the interface structure often changes dynamically during the reaction. In the conventional supported catalysts, the metals at the interface have been extensively studied, while the structural evolution of oxides is often overlooked due to the interference of the bulk phase signal. In this work, CeO₂−CuO inverse catalysts are designed to reveal the dynamic structure evolution of CeO₂ in the CeO₂−CuO system during the water gas shift (WGS) reaction by in situ Raman, in situ XRD, quasi in situ XPS, and near ambient pressure XPS (NAP-XPS). CeO₂ is partially concealed in the CuO phase in the un-pretreated catalyst and gradually exposed to the surface, forming an inverse CeO _x /Cu structure during the reducing process. This structure exhibits a high catalytic activity in the WGS reaction and remains durable under the reductive conditions. When the inverse CeO _x /Cu structure is exposed to the non-redox conditions, the reconfiguration of the reduced oxide is observed which is caused by the oxygen migration of CeO₂. This work explores the structure evolution of CeO₂ in CeO₂−CuO inverse catalyst under different conditions by in situ characterization technique and provides a reference for monitoring the dynamic changes of oxide structure.

Hollow CeO₂ nanoparticles mesoporous defects were prepared by a solid template method, and showed good catalytic performance for the conversion of CO₂ into DMC owing to its abundant mesoporous defects and high oxygen vacancy concentration.

Abstract

The hollow CeO₂ (H-CeO₂) nanoparticles with mesoporous defects structure were prepared by a solid template method under ambient pressure and applied to catalyze the conversion of CO₂ into dimethyl carbonate (DMC). The textural properties of H-CeO₂ were investigated by various characterization techniques. The results showed that H-CeO₂ have higher surface area, more mesoporous defects and higher surface oxygen vacancies concentration than those of conventional CeO₂ with block morphology (C-CeO₂). Therefore, H-CeO₂ exhibited better catalytic performance for the conversion of CO₂ into DMC. Additionally, the Ce(NO₃)₃ ⋅ 6H₂O amount in preparation procedure was important for the formation of hollow structure and mesoporous defects. The DMC yield could reach 4.96 % on H-CeO₂-1.2 (Ce(NO₃)₃ ⋅ 6H₂O amount: 1.2 g) catalyst when the reaction was performed at 140 °C and 4.5 MPa for 4 h. This work proposed a facile strategy for designing CeO₂ catalysts for the CO₂ conversion by creating mesoporous defective structure.

This review systematically analyses recent studies on CO₂ hydrogenation to methanol with a focus put on primary and secondary reactions. Thermodynamic aspects, active sites and reaction mechanisms are discussed. We also provide personal views on possible developments in this area and recommendations for catalytic tests and their evaluation to properly compare different catalysts.

Abstract

Carbon dioxide (CO₂) hydrogenation to methanol (CH₃OH) is one of the most promising approaches to provide this platform chemical and to close carbon cycles. In this minireview, we systematically analyze primary and secondary reactions which can take place in this reaction over Cu-based catalysts. In addition to repeatedly discussed reverse water gas shift reaction (RWGS) and CH₃OH production directly from CO₂, we consider decomposition, dehydration, dehydrogenation, and steam reforming of the desired alcohol. These reactions are usually ignored in the studies dealing with CO₂ hydrogenation to CH₃OH but can worsen the catalyst efficiency. Apart from the corresponding thermodynamic analysis, proposed reaction mechanisms and active sites are described and discussed. The effects of co-fed water, CH₃OH and methyl formate on catalyst performance are critically scrutinized, too. We also provide several criteria for unambiguous comparison of different catalysts in terms of CH₃OH selectivity and their activity.

Ethylene glycol metal carboxylates are excellent catalyst precursors for heterogeneous reactions, or can directly be applied in homogeneous catalysis. Applications beyond catalysis are presented.

Abstract

Ethylene glycol metal carboxylates are suited as low-temperature precursors for M and M_xO_y nanoparticle formation, which are applicable in catalytic heterogeneous reactions including hydrogenations, hydrometalations or C,C cross-couplings. For the synthesis of β-oxo-propyl and enol esters [Ru(CO)₂(PPh₃)₂(O₂CR)₂] complexes are excellent homogeneous catalysts with high regioselectivities. Additionally, applications of the title complexes beyond catalysis are presented.

This review summarizes the application of palladium catalysts in electrocatalytic hydrodechlorination for the removal of chlorinated organic pollutants. Some strategies for modulating palladium to enhance activity are discussed and future developments in the field are outlined.

Abstract

This review summarizes the research progress of palladium (Pd) catalysts in electrocatalytic hydrodechlorination (ECH) for the removal of chlorinated organic pollutants (COPs). ECH technology is a new type of green water treatment technology without secondary pollution, which has excellent removal effect on COPs. Pd is widely used in the field of ECH due to its excellent catalytic properties. However, the easy deactivation and high price of Pd have limited the application of Pd catalysts in practical wastewater treatment. Researchers have improved the performance of Pd catalysts for ECH by improving the morphological structure (dispersion, particle size, crystalline surface) and electronic states (electron-rich Pd, electron-deficient Pd). It is also found that modulation of the adsorption abilities of Pd catalysts can greatly improve the catalytic activity. The factors affecting the stability of Pd catalysts are also investigated, and the future large-scale mature application of ECH technology is envisioned. The ability to prepare single-atom Pd catalysts in a relatively simple way is a future direction, which will achieve 100 % atom utilization and thus significantly reduce the cost of Pd. This review details the frontier research on Pd catalysts in the field of ECH, which can provide some good strategies for related researchers.

Single atom catalysts (SACs) have attracted increasing attention in electrocatalysis due to their unprecedented catalytic activity with excellent atomic utilization efficiency derived from unique electronic states and coordination environments. In photoelectrochemical (PEC) water splitting, atomically dispersed metal catalysts anchored to photoelectrodes offer the breakthrough to outperform the conventional thin-film PEC catalysts by enlarging the catalytic sites and facilitating photogenerated charge carrier kinetics. Herein, we present a comprehensive review of SAC-incorporated photoelectrodes for efficient PEC water splitting. Firstly, the representative characterization techniques for the identification of SACs and investigations in respect of photogenerated charge carrier kinetics and photon-to-current efficiency will be discussed. Then, we will introduce the state-of-the-art PEC-SACs classified into noble metal, non-noble metal, and dual metal SACs. Finally, critical outlooks to realize the full potential of SACs in photoelectrocatalysis will be highlighted.

This review examines the potential of converting cellulose into valuable 5-hydroxymethylfurfural (HMF) for sustainable chemical production. Catalyst types, hydrolysis strategies, and reactor systems are explored for their contributions to improving cellulose-to-HMF conversion. The review also covers challenges, future perspectives, and development directions.

Abstract

The catalytic conversion of lignocellulose-derived carbohydrates, particularly cellulose, into 5-hydroxymethylfurfural (HMF), holds significant potential as a crucial step in the sustainable production of valuable platform chemicals. This review presents the remarkable progress made in the field, with a specific emphasis on the role of heterogeneous catalysts, innovative methods for accelerating cellulose hydrolysis, and the design of flow reactor technologies. The distinctive properties and surface functionalities of catalysts facilitate the efficient breakdown of cellulose's intricate structure, thereby promoting selective hydrolysis leading to HMF formation. Therefore, this review comprehensively examines various categories of heterogeneous catalysts, including metal oxides/phosphates, zeolites, functionalized silica/carbon-based materials, heteropolyacids (HPAs), and metal-organic frameworks (MOFs), highlighting their unique mechanisms and performance in cellulose conversion. Furthermore, the review describes the intriguing progress in hydrolysis strategies (pretreatment techniques and advanced heating systems) that have been crucially involved in overcoming the challenges associated with cellulose recalcitrance and achieving enhanced HMF yields. The synergistic interactions between catalysts and innovative hydrolysis methods have played a central role in the breakthroughs within cellulose conversion technology. Another aspect covered in this work is the advancement in using fixed-/fluidized-bed reactors and slug microreactors for the continuous production of HMF. Lastly, the current challenges and future perspectives are presented to propose the dilemma and development direction for efficient cellulose-to-HMF conversion.