Abstract The breakthrough in the performance of carbon-supported non-noble-metal catalysts lies in the synergistic optimization of geometric size and electronic structure; however, the high surface energy of metals tends to induce agglomeration, and the weak interfacial electronic coupling between metals and carbon makes precise regulation of electronic structure challenging. Herein, an incomplete encapsulation of Ni nanoparticles (Ni NPs) -embedded structure is achieved after the self-assembly of Ni species and halogen-doped carbon dots and the subsequent pyrolysis process. The F atoms, endowed with the strong electron-withdrawing capability, abstract electrons from the outer shell of Ni species, which not only accelerates interfacial electron transfer of the catalyst, thus modulating the d-band center of Ni, but also suppresses the formation of Ni−Ni bonds, thereby weakening the intrinsic driving force for metal agglomeration. Among them, the catalyst Ni@FCDs doped with F atoms exhibits the highest adsorption and dissociation ability for reactant molecules, demonstrated by the extended X-ray absorption fine-structure and density functional theory calculations, and the smallest metal particle size (5.54 nm), thus expressing high catalytic hydrogenation activity. Furthermore, the embedded structure effectively inhibits the sintering of Ni NPs during the reaction, and the metal particle size remains stable after 9 cycles of reaction. The synergistic optimization of geometric size and electronic structure of the metal species induced by the “halogen doping dual regulation” strategy provides an innovative approach for the design of high-performance nickel-based catalysts and deepens the understanding of the structure−activity relationship in carbon-supported metal catalysts.

The development of efficient non-noble metal catalysts for selective hydrogenation of furfural to furfuryl alcohol is of great significance for the high-value conversion of biomass. However, precise regulation of the catalytic microenvironment to synergistically enhance reaction activity and selectivity remains challenging. This study used precipitation hydrothermal method to construct cobalt doped ceria supported iron catalyst and applied it to the efficient catalytic transfer hydrogenation of furfural. The optimized catalyst exhibited excellent catalytic performance and structural stability: a conversion of 99.33% for furfural and a selectivity of 99.50% for furfuryl alcohol could be achieved within 4 h, and there was no significant decrease in activity after 9 cycles of testing. In situ FT-IR spectroscopy and density functional theory calculations revealed that its superiority originated from the deep synergy between bimetallic and localized defects. Specifically, the introduction of iron species significantly enhanced the catalyst's ability to dissociate and activate hydrogen donors; cobalt doping not only promoted the enrichment of moderate basic sites by inducing the formation of oxygen vacancies, but also triggered the downward shift of the average d-band center, promoting substrate adsorption. The cobalt site adjacent to oxygen vacancies (Ov-Co) served as the optimal adsorption center, promoting the formation of the optimal adsorption configuration for furfural. Moreover, the appropriate proportion of iron-cobalt species constructed high concentrations of moderate Lewis acidic sites on the catalyst surface, driving the system to follow a highly selective MPV hydrogen transfer pathway. This work system elucidates the intrinsic mechanism of defect engineering and Lewis acid-base site synergistic enhancement of transfer hydrogenation, providing a novel strategy for the rational design of efficient and stable biomass conversion catalysts.

Catalytic hydrogenation is a key transformation in fine chemical synthesis. Compared with conventional batch processes, continuous-flow processing has emerged as a highly promising approach owing to its enhanced safety, precise control of reaction parameters, and suitability for stable continuous production. However, short residence times demand catalysts with high mass-specific activity, optimized adsorption strength, and rapid site turnover. Herein, amorphous FeOx-modified Pt-xFe/SiO2 catalysts were developed for the continuous-flow selective hydrogenation of 2-chloro-4-nitrotoluene. Structural characterization, kinetic analysis, hydrogen-spillover tests, and DFT calculations reveal that Pt-to-FeOx electron transfer generates electron-deficient Ptδ+ sites and downshifts the Pt d-band center, weakening excessive adsorption of reactants/products and promoting active-site regeneration. Meanwhile, the Pt–FeOx interface enhances hydrogen spillover and facilitates nitro-group hydrogenation. The optimized Pt-3.0Fe/SiO2 exhibits 46% higher mass-specific activity than Pt/SiO2, lowers the apparent activation energy from 42.49 to 34.65 kJ mol−1, and remains stable for over 200 h with target-product yield above 99.5%. It also affords higher conversions than Pt/SiO2 across chloro-, fluoro-, bromo-, and multi-halogenated nitroarenes. These results highlight interfacial electronic modulation and hydrogen spillover as effective descriptors for continuous-flow hydrogenation.

Recognizing substrates based on their molecular characteristics promotes the efficient catalytic conversion of feedstocks. The key to the process of reducing nitrobenzene to p-aminophenol (PAP) lies in the precise control of reaction intermediates (phenylhydroxylamine, PHA), in order to achieve highly selective conversion to the PAP. Herein, we report the design of a catalyst featuring targeted phosphorus-containing carbon encapsulation of Pt particles, which is derived from the coordination between triphenylphosphine and Pt ions. The carbon-encapsulated Pt structure suppresses the rapid hydrogenation of nitrobenzene (NB) to aniline and enhances the catalyst's stability. In-situ FTIR spectroscopy and DFT calculations demonstrate that the Pt@PC catalyst exhibits a significant decrease in the adsorption energy for both NB and PHA. Phosphorus-containing functional groups on the carbon surface facilitate electron transfer from Pt to the carbon layer. This promotes the recognition of NB and PHA based on their electronic structure differences, resulting in enhanced NB adsorption and facilitated PHA desorption. Notably, without surfactant addition, the Pt@3PC catalyst exhibits high activity (100%) and high selectivity (91.44%). Furthermore, the catalyst demonstrates exceptional durability, retaining its performance over 10 consecutive cycles with no detectable loss of activity.

Thermocatalysis, the mainstream approach relative to photocatalysis and electrocatalysis, drives reactions by employing catalysts to lower activation energies with thermal energy. However, thermocatalysis presents issues of inefficient heat transfer and limited reaction performance. Magnetic induction heating (MIH) is a promising thermocatalytic strategy. This study employs a carbon-encapsulated Fe–Ni alloy (Ni–Fe@C) for the catalytic hydrogenation of p‑chloronitrobenzene (p‑CNB) under MIH. The results show that magnetic induction heating generates thermal effects under alternating magnetic field (AMF) conditions, whereas thermal-control experiments demonstrate that thermal effects alone cannot fully account for the observed catalytic enhancement. Experimental characterizations further reveal a close association between spin-related electronic characteristics and the AMF-induced catalytic enhancement, while spin-constrained DFT calculations show that changing the spin configuration affects p-CNB adsorption and reaction barriers. Under mild MIH conditions (35 °C, 20 min), the catalyst achieved 99.9% p-CNB conversion, significantly outperforming conventional heating at 101.1 °C (60.1%). This work demonstrates a “magnetic catalysis” strategy for efficient hydrogenation under mild conditions. Heat-driven catalysis can suffer from poor heat transfer and limited performance. A carbon-coated iron–nickel catalyst uses magnetic fields and spin effects to enable efficient hydrogenation under mild conditions.

Ultrafine metal nanoparticles (NPs) have attracted exhaustive research attention due to their large surface-to-volume ratio, especially in heterogeneous catalysis. However, the intrinsic agglomeration propensity originating from the high chemical potential of metal NPs has emerged as a major bottleneck to their catalytic stability. Herein, we report an electronic confinement strategy to maintain ultrafine Pt NPs under exceedingly harsh conditions. Specifically, the localized electron-richness on the multi-layered graphene is ideally suited for stabilizing Pt NPs, illuminating strong adsorption to decrease the chemical potential and disjoining the agglomeration path of metal NPs for efficient catalytic hydrogenation reaction. The reaction rate of p-CNB to p-CAN is estimated at 1.0 MPa H2 and 40°C, obtaining an impressive of 33.1 molp -CAN∙gPt -1∙h-1 for Pt/Co@NC catalyst, which corresponds to a turnover frequency (TOF) value of up to 6448.9 h-1 with excellent durability of 20 catalytic cycles. Analogously, the catalyst demonstrated excellent activity and stability in the hydrogenation of industrial feedstocks containing 4.0 wt.% inorganic/organic sulfur-containing poisons. Comprehensive investigations testify that the Co-graphene 3d-2p and C-Pt 2p-5d orbital overlapping, coupled with the electron transfer from Co to carbon, disturbs the conjugation effect of graphene π-electrons, causing strengthened Pt-graphene and electron-rich Pt NPs, which simultaneously intensifies catalytic performance and stability.

As a part of the green transformation in fine chemical manufacturing, catalytic hydrogenation technology is evolving from conventional batch processes toward more efficient and safer continuous-flow alternatives. However, diffusion limitation in gas-liquid-solid fixed-bed systems remains inevitable, often masking intrinsic activity and compromising catalyst stability. Herein, a dimensionless confinement ratio (eta = dpore/dPt) was proposed to quantify the spatial matching between pores and metal nanoparticles. Its multiscale regulatory effects on metal electronic structure, molecular diffusion, and catalytic stability were systematically elucidated using the hydrogenation of 2-chloro-4-nitrotoluene as a probe reaction. Increasing eta from 1.03 to 1.50 not only shortened the effective diffusion path but also increased the molecular diffusion coefficient, as confirmed by MD simulations. Meanwhile, DFT calculations revealed that larger eta adjusts the Pt-reactant interaction toward a more appropriate adsorption strength, facilitating both activation and desorption. These confinement-driven advantages collectively resulted in a six-fold enhancement in apparent reaction rate and enabled stable 200 h continuous-flow hydrogenation of 2-chloro-4-nitrotoluene. This work establishes a confinement-ratio-guided design principle that unifies pore structure, diffusion dynamics, electronic modulation, and catalytic stability, offering a general strategy for multiscale optimization of continuous-flow hydrogenation in fine chemicals synthesis.

The key challenges in the coupled hydrogenation-Bamberger rearrangement process for synthesizing paraaminophenol (PAP) from nitrobenzene lie in achieving high selectivity and stable catalysis. Herein, we designed a dual-active-site, nitrogen-doped carbon-supported Pt catalyst for the conversion of nitrobenzene to PAP. The Pt sites boost H2 activation, while the electron-rich pyrrolic N sites leverage hydrogen spillover to achieve efficient semi-hydrogenation of nitrobenzene to phenylhydroxylamine (PHA), thereby boosting PAP selectivity. Combined evidence from the characterizations and DFT calculations confirms that pyrrolic N facilitates electron transfer from Pt to N. DFT calculations further revealed that nitrobenzene preferentially adsorbs on pyrrolic N. And a combination of contact angle measurements, in situ FTIR spectroscopy, and DFT calculations reveals that nitrogen doping facilitates nitrobenzene adsorption while promoting PHA desorption. What's more, the anchoring effect of pyrrolic N on Pt nanoparticles contributes to the enhanced stability of the catalyst. After four hours of treatment in 3 M HCl solution and 1.5 M H2SO4 solution, no metal leaching was detected for Pt/0.3NC. Notably, without surfactant addition, the Pt/0.3NC catalyst exhibits high activity (100%) and high selectivity (93.41%) for the first time. Furthermore, the catalyst demonstrates exceptional durability, retaining its performance over 15 consecutive cycles.

Continuous technology is the future development direction of selective hydrogenation synthesis for fine chemicals. To achieve high hydrogenation performance at atmospheric pressure, it is necessary to construct a suitable microenvironment on the surface of the catalyst to achieve effective mass transfer at the gas-liquid-solid three-phase interface. Ultrafine metal clusters were obtained using Dicyandiamide (DICY) in the hydrothermal process. Subsequently, the alkylsilane was added to construct a respiratory-like microenvironment. (The microenvironment is similar to the respiratory channels, which regulate the entry and exit of substances rhythmically and dynamically, ensuring the continuous and efficient catalytic reaction). The continuous selective hydrogenation of nitroaromatics over Pt-AC(DICY)-C8 in a fixed-bed microreactor showed excellent hydrogenation ability, with the conversion of 2-chloro-4-nitrotoluene reaching 100% and the 3-chloro-4-methylaniline selectivity exceeding 99% within 80 h. The excellent hydrogenation performance is attributed to the highly dispersed Pt clusters, which increase the active sites. The respiratory-like microenvironment promotes the mass transfer of H2 and hydrophobic reactants, increasing the H2 concentration surrounding the Pt active site and the enrichment of reactants. Simultaneously, the respiratory-like microenvironment is conducive to the rapid diffusion of hydrophilic products and prevents excessive hydrogenation. This strategy shows the potential to improve the efficiency and stability of the continuous catalytic hydrogenation reaction.

Encapsulated catalysts have become a new strategy for catalysis in harsh reaction environments due to their unique structural and functional reorganization properties, and they have been widely applied in fields such as electrocatalysis, photocatalysis, and thermocatalysis. In strategies involving encapsulated catalysts, the optimization of electronic properties on the carbon layer surface to enhance reactivity while maintaining adequate encapsulation poses a challenge due to the trade-off between stability, poison resistance, and acid resistance against the performance of metal nanoparticles. Herein, an alloying strategy for Co-Ni bimetal was proposed, which achieves a delicate balance between catalyst activity and stability. Ni plays a pivotal role in promoting the formation of graphitized carbon and the construction of an effective encapsulation structure, thereby ensuring the stability of the catalyst. Co incorporation and alloying with Ni modulates the electronic state and D-band structure within the metallic core, effectively breaking the electronic cloud segregation barrier imposed by the carbon shell. This modulation notably enhances the efficiency of reactions. For the hydrogenation ofp-CNB top-CAN, Co2Ni8@C exhibits an extremely low apparent activation energy (53.40 KJ/mol), as well as > 99 % conversion and selectivity.

Pronounced adsorption of HCl critically hinders the catalytic dehydrochlorination of halogenated hydrocarbons, leading to catalyst degradation or deactivation. Coupling this process with HCl-consuming acetylene hydrochlorination offers an effective strategy to mitigate this issue. Density functional theory (DFT) simulations at the PBE0/ma-TZVP level are employed to investigate the adsorption of reactants on a series of metal chlorides and their Cl- complexes. Based on the adsorption energy data, a variety of co-catalysts with different characteristics are screened and their catalytic mechanisms are systematically investigated. The KCl-CuCl-ionic liquid catalyst has been theoretically proven to be the optimal catalyst, facilitating the dehydrochlorination of chloroalkanes (Delta G = 134.0 kJ mol-1) and acetylene hydrochlorination (Delta G = 124.4 kJ mol-1) through the different dissociation states of ionic liquids and metal salts. Furthermore, KCl inhibits multiple acetylene adsorption, accelerates olefin desorption, and hinders the formation of copper acetylide, thereby ensuring sustained catalytic stability.

Integrating nitrogen is beneficial for increasing defect sites and enhancing catalytic performance and has been a persistent research focus in the structural construction of carbon materials. Nevertheless, the uncontrollable distribution and intricate bonding reactions of nitrogen species within the carbon matrix have posed challenges in precisely regulating nitrogen type and content. Herein, nitrogen-doped carbon quantum dots (NCQDs) served as inhibitors to hinder the generation of graphitic nitrogen with weak electronegativity, thereby facilitating nitrogen configuration engineering. The NCQDs interacted with dicyandiamide to inhibit the polycondensation reaction between triazine units during the carbonization process, thereby synthesizing a porous hybrid carbon with exceptionally high nitrogen content (36.71 at%) and a pyrrolic/pyridinic-N percentage of 90.9 at%. Such high nitrogen content, along with edge nitrogen proportions, was unprecedented compared to conventional methods. As confirmed by experimental characterization and DFT calculations, abundant edge pyrrolic/pyridinic-N atoms facilitated charge transfer, which strengthened the interaction with Pt nanoparticles (NPs) and increased the electron density at the Fermi level, thereby improving the adsorption of the composites to reactants. This work presents an ideal strategy for the development of carbon-based catalysts with high nitrogen content and for studying nitrogen configuration in catalysis.

Carbon-encapsulated metal (CEM) catalysts reconfigure the active site of the catalytic reaction by shifting from the conventional metal to the surface of the carbon material. Carbon-encapsulated structure has attracted wide attention in the fields of electrochemistry, thermal catalysis and photocatalysis. Herein, a nitrogen-doped carbon-encapsulated nickel catalyst was synthesized via hydrothermal synthesis, with pyrrolic N (NPyr) content accounting for 48.4% of the total nitrogen species. Experiments and density functional theory calculations reveal that the five-membered pyrrole ring shares six pi electrons, and its electron cloud density on the carbon surface surpasses that of benzene or pyridine ring, promoting extensive electronic interaction between NPyrC and nickel. The interaction also extends beyond the vicinity of the doping sites and permeates throughout the entire carbon shell, thereby augmenting a greater number of potential active sites on the NC layer. This strengthened delocalized electronic effect imparts specificity in the adsorption and dissociation processes of hydrogen and p-chloronitrobenzene, leading to enhanced catalytic performance in the hydrogenation production of p-chloroaniline. The precise preparation of NPyr-doped CEM catalysts demonstrates its huge potential for industrial applications.

Establishing structural defects is a perspective way to increase the catalytic hydrogenation reaction. Toward Sabatier optimization for hydrogenation reaction with defect density offers guidance for designing optimal catalysts with the highest performance. A controllable synthesis strategy is reported for Co@NC-x catalyst induced by defect density. A series of N-doped carbon-based defective Co@NC-x catalysts with different defect densities ranging from 1.5 × 1011 to 1.9 × 1011 cm-2 via high-temperature sublimation strategy is obtained. The results show that the volcano curves are observed between defect density and catalytic hydrogenation performance with a summit at a moderate defect density of 1.7 × 1011 cm-2, matched well with Sabatier phenomenon. Remarkably, the defect density on the graphene-like shell serves as descriptor to the adsorbate state and consequently the catalytic activity. However, to the best of knowledge, the Sabatier phenomenon in hydrogenation reactions at the defect scale in 3D graphene-like encapsulated metal (3D-GEM) catalysts has not been reported. This work highlights the meaning of defect-density effect on catalytic hydrogenation reaction, supplying meaningful guidance for the rational design of more efficient and durable defective 3D-GEM catalyst.

The catalytic alkaline dehydrochlorination process, characterized by high atom economy, stands as a prevalent method in the synthesis of valuable alkene halides. Nonetheless, the efficacy of ionic liquids (ILs) as catalysts for dehydrochlorination is hindered by challenges such as swift deactivation attributed to decomposition and reduced selectivity without clear causative factors. This investigation employs a systematic approach, integrating Density Functional Theory (DFT) simulations with experimental methodologies, to delve into the mechanisms of IL-catalyzed dehydrochlorination, aiming to elucidate both stabilization strategies and catalytic pathways. The examination of thermal decomposition rates is rooted in a meticulous assessment of the energy barriers associated with decomposition and dissociation processes. The active role of free Cl-is established, albeit its acidification by HCl, which results in diminished catalytic activity. To counteract this acidifying influence, a novel active site denoted as [Cl-KCl]- is conceptually devised to mitigate such effects. Through the strategic implementation of cationic fixation, the IL-KCl combination catalyst is synthesized and empirically confirmed to demonstrate augmented acid resistance while upholding a consistent reaction selectivity of approximately 85 %. This contrasts starkly with the declining catalytic selectivity observed with IL in isolation, plummeting from 85% to 65%. Consequently, the IL-KCl combination catalyst emerges as a promising option for alkali catalyzed dehydrochlorination, offering enhanced stability and sustained high selectivity throughout the catalytic process.

Biomass provides a promising source of carbon for obtaining environment-friendly carbon materials, but obtaining heteroatom-doped carbon materials (HDCMs) from biomass directly by a green method still remains challenging. This study successfully synthesized nitrogen and phosphorus co-doped porous carbon materials (Y-NPC) by the simple in situ pyrolysis of renewable yeast mixed with water from 800 to 950 degrees C. Various characterization methods show that nitrogen and phosphorus are doped into the carbon skeleton and mainly exist in the forms of graphite-N, pyridine-N, C-P, P-N, and P-O states. The catalyst Y-NPC-900 degrees C with a 3D hierarchical porous structure and high P-N content exhibited superior nitro hydrogenation performance and reaction stability using molecular hydrogen and hydrazine hydrate as hydrogen sources under mild conditions. Density functional theory (DFT) calculations and experiments attributed the exceptional catalytic performance to hydrogen activation and the good adsorption ability of substrates over N, P co-doped carbon (NPC). Therefore, this research proposes an eco-friendly and simple synthesis strategy for in situ N, P co-doping metal-free carbon catalysts derived from biomass, showing the significance of N, P co-doping and single N- or P-monodoping in the charge distribution of carbon materials.

The utilization of encapsulated catalysts significantly enhances the stability of metal catalysts by effectively isolating the interaction between poisons and metals. However, striking a delicate balance between activity and stability poses a challenge. Herein, an alloying strategy for Co-Ni bimetal was proposed to enhance the catalytic performance of the encapsulation structure. Ni is responsible for the formation of graphitized carbon and encapsulation structure. The addition of Co forms an alloy phase with Ni to form a metal core, and adjusts the electronic state and D-band structure in the metal core. Compared with pure Ni, the Co-Ni alloy broke the electron cloud segregation restriction of the metal core to the carbon shell. And, the bimetallic encapsulated catalyst showed excellent catalytic performance. For the hydrogenation of p-chloronitrobenzene to chloroaniline, Co2Ni8@C for exhibited an extremely low apparent activation energy (41.989 KJ/mol), as well as >99% conversion and selectivity.

The inferior stability of noble metal-based thermocatalysts for effective catalytic hydrogenation reaction severely restricts the production of value-added fine chemicals under a strong acid reaction environment. Herein, a shield effect strategy is proposed to establish ultrafine metal NPs with oxidation layers encapsulated in S- and N-doped graphene with stability for robust coupling-efficient catalytic hydrogenation and acid-catalyzed Bamberger rearrangement of nitrobenzene to p-aminophenol. The unconventional structure based on shield effect comprises an oxide layer with dislocation and tensile strain, enabling sluggish dissociation of H-2 to H*, coupled with a local electron-enriched S,N-doped graphene shell, restraining the ultrafast hydrogenation rate to form aniline and enhancing the stability of the catalyst. In addition, the experimental characterization and density functional theory simulation further manifest that the oxidizing effect of nitric acid reconstitutes the charge of the graphene shell, rendering it highly specific for phenylhydroxylamine rearrangement to obtain p-aminophenol with high selectivity. The proposed strategy in this work showcases a universal and practicable method for pinpoint modulation of the inherent performance of attainable metal nanoparticles with a programmable graphene shell microenvironment toward highly specific catalysis under the strong acid reaction environment.

The distribution of gas-liquid two-phase flow is one of significant effects on heterogeneous catalytic reactions. Ceramic membrane gas distributors (CMGD) were applied in improving gas-liquid distribution, and flow behavior of gas as dispersed phase in liquid phase was visualized via high-speed photograph. The average diameters of multi-scale bubbles were measured and modeled ranging from 10-5 to 10-2 m. The coalescence and trajectory of bubbles during rising process were observed, and two typical trajectories straight and spiral types were tracked. In order to inhibit coalescence of bubbles during rising process, internals manufactured by 3D printing were installed in the channel of ceramic membrane. The average bubble size of CMGD decreases 12 % from 392 to 345 μm compared to that of the original CMGD. The CMGD with internals enhances the heterogeneous catalytic reaction performance via providing large quantity of stabile multi-scale bubbles which could match the porous structure of catalyst.

It is extremely ideal but also a challenge to develop stable and effective hydrogenation catalysts with high activity for the product of value-added fine chemicals. Herein, we report a in situ S-doped NC graphene-like shell encapsulated cobalt nanoparticles catalyst (Co@S-NC) for the hydrogenation of nitroarenes. The introduction of sulphur into NC graphene-like shell surface enhances the electron disturbance and promotes the electron transfer interior metal into external graphene-like shell, accompanying with triggering hydrogenation reaction. For Co@S-NC catalyst, the unusual coordination environment between Co NPs metal and NC graphene-like shell decreases limitation of the graphene-like layer and possesses an eminent catalytic activity and reusability. The Density functional theory (DFT) calculations indicate that CoN3S1 within Co@S-NC, the center of S-doped NC graphene-like shell encapsulated cobalt nanoparticles, is an active site for the hydrogenation reaction and has a lower energy barrier 1.03 eV for the rate-determining step than CoN4 of Co@S-NC catalyst. These researches verify that the Co@S-NC, excellent graphitic carbon encapsulation material, manifests a wide application for increasing the catalytic activity of graphene-like shell embedded catalyst.