Enhanced Hydrogenation Performance Over CeO 2 Quantum Dots Modified Pt/SiC Catalyst Ignited by Hydrogen Spillover Effect

The exposed facets of supported metal catalysts play a crucial role in catalytic hydrogenation performance. However, the internal relationship between the support crystal facet and catalytic performance needs to be further explored. Herein, a series of well-defined Pt/Co3O4-x catalysts are fabricated with similar Pt nanoparticle sizes, identical metal loadings, and tailored Co3O4 crystal facets (x = o, t, c; where "o", "t", and "c" denote Co3O4 exposing predominantly (111), mixed (111)/(100), and (100) facets, respectively). The electronic structure of Pt nanoparticles and the hydrogen spillover capability of Pt/Co3O4 are modulated by exposing different crystal facets of Co3O4. For the 4-nitrophenol (4-NP) hydrogenation reaction with H2 as the hydrogen source, the Pt/Co3O4-o catalyst with more Pt0 species and stronger hydrogen spillover capability exhibits the best hydrogenation activity with a turnover frequency (TOF) of 164.2 h-1. Mechanistic studies indicate that, compared with Pt/Co3O4-c, the Pt/Co3O4-o exhibits weaker adsorption and activation of the nitro group, while its ability to activate H2 is stronger. The enhanced catalytic activity of Pt/Co3O4-o is attributed to promoted hydrogen activation and spillover. This work highlights support crystal facet engineering for regulating the electronic structure and hydrogen spillover effect, which provides in-depth insight into catalyst design and hydrogenation mechanism.

Hydrogen spillover enabled active Cu sites for methanol synthesis from CO2 hydrogenation over Pd doped CuZn catalysts

Hydrogen spillover effect has recently garnered a lot of attention in the field of electrocatalytic hydrogen evolution reactions. A new avenue for understanding the dynamic behavior of atomic migration in which hydrogen atoms moving on a catalyst surface was opened up by the setup of the word “hydrogen spillover.” However, there is currently a dearth of thorough knowledge regarding the hydrogen spillover effect. Currently, the advancement of sophisticated characterization procedures offers progressively useful information to enhance our grasp of the hydrogen spillover effect. The understanding of material fabrication for hydrogen spillover effect has erupted. Considering these factors, we made an effort to review most of the articles published on the hydrogen spillover effect and carefully analyzed the aspect of material fabrication. All of our attention has been directed toward the molecular pathway that leads to improve hydrogen evolution reactions performance. In addition, we have attempted to elucidate the spillover paths through the utilization of DFT calculations. Furthermore, we provide some preliminary research suggestions and highlight the opportunities and obstacles that are still to be confronted in this study area.

Unveiling the mysteries of hydrogen spillover phenomenon in hydrogen evolution reaction: Fundamentals, evidence and enhancement strategies

The widespread application of water electrolysis is hindered by the inefficient hydrogen evolution reaction (HER) kinetics at industrial‐scale current density. Hydrogen spillover offers a promising strategy to circumvent thermodynamic limitations of volcano diagrams, while its implementation on binary‐component systems remains complex nanomaterial engineering to overcome sluggish interfacial proton migration. Here, an in situ electrochemical reconstruction strategy is reported to optimize hydrogen spillover pathways, which is verified on classic tungsten oxide‐based catalysts (Ru/WOx) with hydrogen spillover effect. Operando characterization and control experiments confirm dynamic oxidation of Ru species during HER operation, which is accompanied with facilitated proton transformation and insertion in WOx lattice. The theoretical calculations reveal that the in situ reconstruction of catalyst dilutes interfacial electron density and lowers thermodynamic barriers for hydrogen migration, thus leading to thermo‐neutral RuO x /WO 2 interfacial sites. The reconstructed catalyst achieves a low overpotential of 317 mV at 1000 mA cm −2 in alkaline media, with exceptional stability over 500 h. This work elucidates the interplay between in situ reconstruction and proton transfer dynamics, providing new insights for the design of electrocatalysts.

Interfacial hydrogen spillover on Pt/C3N4 enables industrial-level alkaline hydrogen evolution reaction.

The hydrogen spillover effect (HSPE) on metal catalysts supported on non-reducible oxides is still controversial. Our investigation shows that the controversy comes from a misunderstanding about statements of pioneer works. Papers accepting or rejecting the HSPE and based on these statements were found both not pertinent. Factually, the oxide surface OH groups play an important role in the formation, extent, and reactivity of hydrogen spillover. We propose that hydrogen spillover would consist in H/OH pairs, produced by an interfacial dehydroxylation then diffusing over the support by a thermodynamically neutral H/OH exchange mechanism and not by an H atom hopping process, as generally believed. The hydrogen atoms of the H/OH pairs may be consumed chemically or desorb as H2, giving rise to □/O2- pairs (where □ denotes an oxygen vacancy) which, in turn, may further dissociate H2, renewing the H/OH active sites. H/OH and □/O2 constitute conjugated pairs in the hydrogen spillover effect.

Hydrogen migration from metal particles to the support, known as hydrogen spillover, has provided insights for designing highly efficient catalysts in catalytic processes involving hydrogen. A facile and controllable strategy is highly desired to achieve an effective hydrogen spillover effect on nonreducible oxides for catalytic performance optimization and clarifying the catalytic function of hydrogen spillover. Here, we provide an organic molecular decoration (OMD) strategy obtained by the molecular layer deposition-like pulse method for facilitating hydrogen spillover over the nonreducible silica support. After decorating with the fluoroalkylsilane (FAS) molecular layer, the hydrogen spillover effect over the catalysts (xFAS-Pt/SBA-15) is greatly enhanced due to the presence of carbonaceous species compared with the original Pt/SBA-15. The amount of hydrogen spillover can also be precisely regulated by controlling the FAS pulse number. For cinnamaldehyde hydrogenation, xFAS-Pt/SBA-15 presents superior catalytic performance versus its untreated counterpart and the sample decorated via the traditional method. Also, the catalytic activity varies based on the FAS pulse number, showing a linear correlation with the amount of hydrogen spillover. The altered adsorption behavior of the reactant plays an important role in the hydrogenation selectivity. This facile OMD strategy for efficient hydrogen spillover is general and may have potential applications in many heterogeneous reactions.

This literature review examines the hydrogen spillover mechanisms on copper on zinc oxide (Cu/ZnO)-based catalysts for CO2 hydrogenation to methanol. The production of methanol from CO2 is an attractive process for mitigating greenhouse gas emissions and producing a valuable chemical feedstock. Cu/ZnO-based catalysts are known to exhibit high activity and selectivity towards methanol production and the hydrogen spillover effect is believed to play a crucial role in their performance. The review discusses the current understanding of the hydrogen spillover mechanism, including the nature of the active sites and the factors that affect spillover efficiency. It also summarises recent advances in catalyst design, such as the use of promoters and dopants, to enhance the hydrogen spillover effect and improve catalytic performance. This article provides a comprehensive overview of the hydrogen spillover mechanism on Cu/ZnO-based catalysts for CO2 hydrogenation to methanol, highlighting the potential of this technology for sustainable methanol production.

Bimetallic Pt-Fe catalysts supported on mesoporous TS-1 microspheres for the liquid-phase selective hydrogenation of cinnamaldehyde

Enhanced photocatalytic hydrogen evolution of Ru/TiO2-x via oxygen vacancy-assisted hydrogen spillover process

Cinnamic compound metabolism in human skin and the role metabolism may play in determining relative sensitisation potency

Synthesis of aluminum doped MIL-100(Fe) compounds for the one-pot photocatalytic conversion of cinnamaldehyde and benzyl alcohol to the corresponding alcohol and aldehyde under anaerobic conditions

The hydrogen spillover effect (HSPE) is an appealing interfacial phenomenon in the hydrogen evolution reaction (HER). However, the application of HSPE in transition metal-based electrocatalytic materials is still at an exploratory stage due to the unclear reaction mechanism and the complex electrolytic environment. How to apply the HSPE as a functionalized strategy for designing efficient electrocatalytic materials becomes the research focus. In order to better understand the role of HSPE in electrocatalytic water splitting, this chapter first introduces the basic principles of HSPE, followed by a review of electrocatalysts utilizing HSPE in acidic and alkaline electrolysis. The underlying mechanism of HSPE for improving the HER performance and the designing principles of HER catalysts are then analyzed. Lastly, the present issues in this research area and the promising research directions are proposed. Hopefully, this chapter can provide meaningful guidance for designing cost-effective and efficient HER electrocatalysts by applying the HSPE.

The construction of multifunctional catalytically active sites and application of their synergistic effects in heterogeneous catalysis are pivotal for achieving cinnamaldehyde (CAL) highly efficiently and selectively converting to high‐value chemicals. This study reports the Pt/CoZrO x catalysts with highly dispersed platinum, where Pt facilitates hydrogen adsorption, activation, and dissociation; the Co‐related sites promote preferential adsorption of CAL. This rational design significantly enhances selective hydrogenation of CAL, obtaining 64.0% CAL conversion and 82.8% selectivity to cinnamyl alcohol (COL) with a hydrogenation reaction rate of 174.8 mol CAL mol Pt −1 h −1 under mild reaction conditions (60°C). Pt/CoZrO x also exhibits remarkable stability, maintaining its catalytic activity and selectivity over five consecutive cycles without significant degradation. In addition, this work indicates that the reason for selectivity enhancement may be the synergistic effect of multiple active sites, providing fundamental insights for the rational design of highly efficient and selective catalysts for CAL selective hydrogenation.