Design Of Catalysts Research Articles

Screening the optimal Cox/CeO2(110) (x = 1–6) catalyst for methane activation in coalbed gas

The challenges posed by energy and environmental issues have forced mankind to explore and utilize unconventional energy sources. It is imperative to convert the abundant coalbed gas (CBG) into high value-added products, i.e., selective and efficient conversion of methane from CBG. Methane activation, known as the “holy grail”, poses a challenge to the design and development of catalysts. The structural complexity of the active metal on the carrier is of particular concern. In this work, we have studied the nucleation growth of small Co clusters (up to Co6) on the surface of CeO2(110) using density functional theory, from which a stable loaded Co/CeO2(110) structure was selected to investigate the methane activation mechanism. Despite the relatively small size of the selected Co clusters, the obtained Cox/CeO2(110) exhibits interesting properties. The optimized Co5/CeO2(110) structure was selected as the optimal structure to study the activation mechanism of methane due to its competitive electronic structure, adsorption energy and binding energy. The energy barriers for the stepwise dissociation of methane to form CH3*, CH2*, CH*, and C* radical fragments are 0.44, 0.55, 0.31, and 1.20 eV, respectively, indicating that CH* dissociative dehydrogenation is the rate-determining step for the system under investigation here. This fundamental study of metal-support interactions based on Co growth on the CeO2(110) surface contributes to the understanding of the essence of Co/CeO2 catalysts with promising catalytic behavior. It provides theoretical guidance for better designing the optimal Co/CeO2 catalyst for tailored catalytic reactions.

Discovery of Alloy Catalysts Beyond Pd for Selective Hydrogenation of Reformate via First‐Principle Screening with Consideration of H‐Coverage

AbstractThe highly selective hydrogenation to remove olefins is a significant refining approach for the reformate. Herein, a library of transition metal for reformate hydrogenation is tested experimentally to validate the predictive level of catalytic activity from our theoretical framework, which combines ab initio calculations and microkinetic modeling, with consideration of surface H‐coverage effect on hydrogenation kinetics. The favorable H coverage of specific alloy surface under relevant hydrogenation condition, is found to be determined by its corresponding alloy composition. Besides, olefin hydrogenation rate is determined as a function of two descriptors, i.e. H coverage and binding energies of atomic hydrogen, paving the way to computationally screen on metal component in the periodic table. Evaluation of 172 bimetallic alloys based on the activity volcano map, as well as benzene hydrogenation rate, identifies prospective superior candidates and experimentally confirms that Zn3Ir1 outperforms pure Pd catalysts for the selective hydrogenation refining of reformate. The insights into H‐coverage‐related microkinetic modelling have enabled us to both theoretically understand experimental findings and identify novel catalysts, thus, bridging the gap between first‐principle simulations and industrial applications. This work provides useful guidance for experimental catalyst design, which can be easily extended to other hydrogenation reaction.

Stable Pentagonal Layered Palladium Diselenide Enables Rapid Electrosynthesis of Hydrogen Peroxide.

Electrosynthesis of hydrogen peroxide (H2O2) via the two-electron oxygen reduction reaction (2e- ORR) is promising for various practical applications, such as wastewater treatment. However, few electrocatalysts are active and selective for 2e- ORR yet are also resistant to catalyst leaching under realistic operating conditions. Here, a joint experimental and computational study reveals active and stable 2e- ORR catalysis in neutral media over layered PdSe2 with a unique pentagonal puckered ring structure type. Computations predict active and selective 2e- ORR on the basal plane and edge of PdSe2, but with distinct kinetic behaviors. Electrochemical measurements of hydrothermally synthesized PdSe2 nanoplates show a higher 2e- ORR activity than other Pd-Se compounds (Pd4Se and Pd17Se15). PdSe2 on a gas diffusion electrode can rapidly accumulate H2O2 in buffered neutral solution under a high current density. The electrochemical stability of PdSe2 is further confirmed by long device operational stability, elemental analysis of the catalyst and electrolyte, and synchrotron X-ray absorption spectroscopy. This work establishes a new efficient and stable 2e- ORR catalyst at practical current densities and opens catalyst designs utilizing the unique layered pentagonal structure motif.

Discovery of Alloy Catalysts Beyond Pd for Selective Hydrogenation of Reformate via First-Principle Screening with Consideration of H-Coverage.

The highly selective hydrogenation to remove olefins is a significant refining approach for the reformate. Herein, a library of transition metal for reformate hydrogenation is tested experimentally to validate the predictive level of catalytic activity from our theoretical framework, which combines ab initio calculations and microkinetic modeling, with consideration of surface H-coverage effect on hydrogenation kinetics. The favorable H coverage of specific alloy surface under relevant hydrogenation condition, is found to be determined by its corresponding alloy composition. Besides, olefin hydrogenation rate is determined as a function of two descriptors, i.e. H coverage and binding energies of atomic hydrogen, paving the way to computationally screen on metal component in the periodic table. Evaluation of 172 bimetallic alloys based on the activity volcano map, as well as benzene hydrogenation rate, identifies prospective superior candidates and experimentally confirms that Zn3Ir1 outperforms pure Pd catalysts for the selective hydrogenation refining of reformate. The insights into H-coverage-related microkinetic modelling have enabled us to both theoretically understand experimental findings and identify novel catalysts, thus, bridging the gap between first-principle simulations and industrial applications. This work provides useful guidance for experimental catalyst design, which can be easily extended to other hydrogenation reaction.

The “4 + 1” strategy fabrication of iron single-atom catalysts with selective high-valent iron-oxo species generation

Single-atom catalysts (SACs) with atomic dispersion active sites have exhibited huge potentials in peroxymonosulfate (PMS)-based Fenton-like chemistry in water purification. However, four-N coordination metal (MN4) moieties often suffer from such problems as low selectivity and narrow workable pH. How to construct SACs in a controllable strategy with optimized electronic structures is of great challenge. Herein, an innovative strategy (i.e., the "4 + 1" fabrication) was devised to precisely modulate the first-shell coordinated microenvironment of FeN4 SAC using an additional N (SA-FeN5). This leads to almost 100% selective formation of high-valent iron-oxo [Fe(IV)═O] (steady-state concentration: 2.00 × 10-8 M) in the SA-FeN5/PMS system. In-depth theoretical calculations unveil that FeN5 configuration optimizes the electron distribution of monatomic Fe sites, which thus fosters PMS adsorption and reduces the energy barrier for Fe(IV)═O generation. SA-FeN5 was then attached to polyvinylidene difluoride membrane for a continuous flow device, showing long-term abatement of the microcontaminant. This work furnishes a general strategy for effective PMS activation and selective high-valent metal-oxo species generation by high N-coordination number regulation in SACs, which would provide guidance in the rational design of superior environmental catalysts for water purification.

Active learning of ternary alloy structures and energies

Machine learning models with uncertainty quantification have recently emerged as attractive tools to accelerate the navigation of catalyst design spaces in a data-efficient manner. Here, we combine active learning with a dropout graph convolutional network (dGCN) as a surrogate model to explore the complex materials space of high-entropy alloys (HEAs). We train the dGCN on the formation energies of disordered binary alloy structures in the Pd-Pt-Sn ternary alloy system and improve predictions on ternary structures by performing reduced optimization of the formation free energy, the target property that determines HEA stability, over ensembles of ternary structures constructed based on two coordinate systems: (a) a physics-informed ternary composition space, and (b) data-driven coordinates discovered by the Diffusion Maps manifold learning scheme. Both reduced optimization techniques improve predictions of the formation free energy in the ternary alloy space with a significantly reduced number of DFT calculations compared to a high-fidelity model. The physics-based scheme converges to the target property in a manner akin to a depth-first strategy, whereas the data-driven scheme appears more akin to a breadth-first approach. Both sampling schemes, coupled with our acquisition function, successfully exploit a database of DFT-calculated binary alloy structures and energies, augmented with a relatively small number of ternary alloy calculations, to identify stable ternary HEA compositions and structures. This generalized framework can be extended to incorporate more complex bulk and surface structural motifs, and the results demonstrate that significant dimensionality reduction is possible in thermodynamic sampling problems when suitable active learning schemes are employed.

Metal Hydrogen-Bonded Organic Frameworks as Open Lewis Acid Catalysts for Two Types of CO2 Transformations.

Efficient and multiple CO2 utilization into high-value-added chemicals holds significant importance in carbon neutrality and industry production. However, most catalysis systems generally exhibit only one type of CO2 transformation with the efficiency to be improved. The restricted abundance of active catalytic sites or an inefficient utilization rate of these sites results in the constraint. Consequently, we designed and constructed two metal hydrogen-bonded organic frameworks (M-HOFs) {[M3(L3-)2(H2O)10]·2H2O}n (M = Co (1), Ni (2); L = 1-(4-carboxyphenyl)-1H-pyrazole-3,5-dicarboxylic acid) in this research. 1 and 2 are well-characterized, and both show excellent stability. The networks connected by multiple hydrogen bonds enhance the structural flexibility and create accessible Lewis acidic sites, promoting interactions between the substrates and catalytic centers. This enhancement facilitates efficient catalysis for two types of CO2 transformations, encompassing both cycloaddition reactions with epoxides and aziridines to afford cyclic carbonates and oxazolidinones. The catalytic activities (TON/TOF) are superior compared with those of most other catalysts. These heterogeneous catalysts still exhibited high performance after being reused several times. Mechanistic studies indicated intense interactions between the metal sites and substrates, demonstrating the reason for efficient catalysis. This marks the first instance on M-HOFs efficiently catalyzing two types of CO2 conversions, finding important significance for catalyst design and CO2 utilization.

Unveiling Synergetic Photocatalytic Activity from Heterometallic Ti/Ce Clusters.

Titanium-oxo clusters, with their robust structure and suitable optical and electronic properties, have been widely investigated as photocatalysts. Heterometallic Ti/M-oxo clusters provide additional tunability and functionality, which enable systematic structure-activity investigations to elucidate the reaction mechanisms and improve the catalyst design. Incorporating cerium into Ti-oxo clusters can provide additional redox (CeIV/CeIII) and oxygen harvesting ability, but to date, only a limited number of structurally defined titanium-cerium (Ti/Ce) clusters have been reported due to their synthetic challenges. Herein, we report the synthesis and photocatalytic properties of two structurally defined Ti/Ce-oxo clusters, Ti8Ce2(BA)16 and Ti9Ce4(BA)20, as well as a TiCe-BA cluster with a calculated formula of Ti20Ce9O36(BA)42. Photocatalytic study of these clusters demonstrates that the amount of Ce3+ species greatly impacts its photocatalytic oxidation performance, and their superior photocatalytic reactivity toward aerobic alcohol oxidation can be contributed to the synergistic effects of the multiple radical species generated upon light absorption. This work represents a significant milestone in the construction of stable Ti/Ce-oxo clusters, enriching the current library of known heterometallic Ti/M-oxo clusters, and providing a series of crystalline materials with great promise of photoluminescence and photovoltaic chemistry.

Electrosynthesis of Verdoheme and Biliverdin Derivatives Following Enzymatic Pathways.

Artificial syntheses of biologically active molecules have been fruitful in many bioinspired catalysis applications. Specifically, verdoheme and biliverdin, bearing polypyrrole frameworks, have inspired catalyst designs to address energy and environmental challenges. Despite remarkable progress in benchtop synthesis of verdoheme and biliverdin derivatives, all reported syntheses, starting from metalloporphyrins or inaccessible biliverdin precursors, require multiple steps to achieve the final desired products. Additionally, such synthetic procedures use multiple reactants/redox agents and involve multistep purification/extraction processes that often lower the yield. However, in a single step using atmospheric oxygen, heme oxygenases selectively generate verdoheme or biliverdin from heme. Motivated by such enzymatic pathways, we report a single-step electrosynthesis of verdoheme or biliverdin derivatives from their corresponding meso-aryl-substituted metalloporphyrin precursors. Our electrosynthetic methods have produced a copper-coordinating verdoheme analog in >80% yield at an applied potential of 0.65 V vs ferrocene/ferrocenium in air-exposed acetonitrile solution with a suitable electrolyte. These electrosynthetic routes reached a maximum product yield within 8 h of electrolysis at room temperature. The major products of verdoheme and biliverdin derivatives were isolated, purified, and characterized using electrospray mass spectrometry, absorption spectroscopy, cyclic voltammetry, and nuclear magnetic resonance spectroscopy techniques. Furthermore, X-ray crystallographic data were collected for select cobalt (Co)- and Cu-chelating verdoheme and metal-free biliverdin products. Electrosynthesis routes for the selective modification at the macrocycle ring in a single step are not known yet, and therefore, we believe that this report would advance the scopes of electrosynthesis strategies.

Bridging Atom Engineering for Low-Temperature Oxygen Activation in a Robust Metal-Organic Framework.

Achieving active site engineering at the atomic level poses a significant challenge in the design and optimization of catalysts for energy-efficient catalytic processes, especially for a reaction with two reactants competitively absorbed on catalytic active sites. Herein, we show an example that tailoring the local environment of cobalt sites in a robust metal-organic framework through substituting the bridging atom from -Cl to -OH group leads to a highly active catalyst for oxygen activation in an oxidation reaction. Comprehensive characterizations reveal that this variation imparts drastic changes on the electronic structure of metal centers, the competitive reactant adsorption behavior, and the intermediate formation. As a result, exceptional low-temperature CO oxidation performance was achieved with T25(Temperature for 25 % conversion)=35 °C and T100 (Temperature for 100 % conversion)=150 °C, which stands out from existing MOF-based catalysts and even rivals many noble metal catalysts. This work provides a guidance for the rational design of catalysts for efficient oxygen activation for an oxidation reaction.

Bridging Atom Engineering for Low‐Temperature Oxygen Activation in a Robust Metal–Organic Framework

AbstractAchieving active site engineering at the atomic level poses a significant challenge in the design and optimization of catalysts for energy‐efficient catalytic processes, especially for a reaction with two reactants competitively absorbed on catalytic active sites. Herein, we show an example that tailoring the local environment of cobalt sites in a robust metal–organic framework through substituting the bridging atom from −Cl to −OH group leads to a highly active catalyst for oxygen activation in an oxidation reaction. Comprehensive characterizations reveal that this variation imparts drastic changes on the electronic structure of metal centers, the competitive reactant adsorption behavior, and the intermediate formation. As a result, exceptional low‐temperature CO oxidation performance was achieved with T25(Temperature for 25 % conversion)=35 °C and T100 (Temperature for 100 % conversion)=150 °C, which stands out from existing MOF‐based catalysts and even rivals many noble metal catalysts. This work provides a guidance for the rational design of catalysts for efficient oxygen activation for an oxidation reaction.

Modulating the Microstructure and Surface Acidity of MnO2 by Doping-Induced Phase Transition for Simultaneous Removal of Toluene and NOx at Low Temperature.

It is a great challenge to remove VOCs and NOx simultaneously from flue gas in nonelectric industries. This study focuses on the construction of Fe-MnO2 catalysts that perform well in the simultaneous removal of toluene and NOx at low temperatures. Utilizing the Fe-induced phase transition of MnO2, Fe-MnO2-F&R catalysts with a composite morphology of nanoflowers and nanorods were successfully prepared that provided an abundant microporous structure to facilitate the diffusion of molecules of different sizes. Through in-depth investigation of the active sites and reaction mechanism, we discovered that Fe-induced phase transition could modulate the surface acidity of Fe-MnO2-F&R. The higher concentration of surface Mn4+ provided numerous Brønsted acid sites, which effectively promoted the activation of toluene to reactive intermediates, such as benzyl alcohol/benzoate/maleic acid. Simultaneously, Fe provided a large number of Lewis acid sites that anchor and activate NH3 species, thereby inhibiting NH3 nonselective oxidation. Furthermore, additional Brønsted acid sites were generated during the simultaneous reaction process, enhancing toluene activation. Consequently, the simultaneous removal of toluene and NOx was achieved through regulation of the physical structure and the concentration of acidic sites. The present work provides new insights into the rational design of bifunctional catalysts for the synergistic control of VOCs and NOx emissions.

Phase Engineering and Dispersion Stabilization of Cobalt toward Enhanced Hydrogen Evolution.

Phase engineering is promising to increase the intrinsic activity of the catalyst toward hydrogen evolution reaction (HER). However, the polymorphism interface is unstable due to the presence of metastable phases. Herein, phase engineering and dispersion stabilization are applied simultaneously to boost the HER activity of cobalt without sacrificing the stability. A fast and facile approach (plasma cathodic electro deposition) is developed to prepare cobalt film with a hetero-phase structure. The polymorphs of cobalt are realized through reduced stacking fault energy due to the doping of Mo, and the high temperature treatment resulted from the plasma discharge. Meanwhile, homogeneously dispersed oxide/carbide nanoparticles are produced from the reaction of plasma-induced oxygen/carbon atoms with electro-deposited metal. The existence of rich polymorphism interface and oxide/carbide help to facilitate H2 production by the tuning of electronic structure and the increase of active sites. Furthermore, oxide/carbide dispersoid effectively prevents the phase transition through a pinning effect on the grain boundary. As-prepared Co-hybrid/CoO_MoC exhibits both high HER activity and robust stability (44mV at 10mA cm-2, Tafel slope of 53.2mV dec-1, no degradation after 100 h test). The work reported here provides an alternate approach to the design of advanced HER catalysts for real application.

Regulating Surface Dipole Moments of TiO2 for the pH-Universal Cathodic Fenton-Like Process.

Although electro-Fenton (EF) processes can avoid the safety risks raised by concentrated hydrogen peroxide (H2O2), the Fe(III) reduction has always been either unstable or inefficient at high pH, resulting in catalyst deactivation and low selectivity of H2O2 activation for producing hydroxyl radicals (•OH). Herein, we provided a strategy to regulate the surface dipole moment of TiO2 by Fe anchoring (TiO2-Fe), which, in turn, substantially increased the H2O2 activation for •OH production. The TiO2-Fe catalyst could work at pH 4-10 and maintained considerable degradation efficiency for 10 cycles. Spectroscopic analysis and a theoretical study showed that the less polar Fe-O bond on TiO2-Fe could finely tune the polarity of H2O2 to alter its empty orbital distribution, contributing to better ciprofloxacin degradation activity within a broad pH range. We further verified the critical role of the weakened polarity of H2O2 on its homolysis into •OH by theoretically and experimentally investigating Cu-, Co-, Ni-, Mn-, and Mo-anchored TiO2. This concept offers an avenue for elaborate design of green, robust, and pH-universal cathodic Fenton-like catalysts and beyond.

Earth Abundant Transition Metal Catalysts: New and Efficient Tools for Hydrophosphination and Oxyphosphination of Alkenes and Alkynes

Hydrophosphination and oxyphosphination are two important topical reactions in order to prepare organophosphorus derivatives from unsaturated derivatives such as alkenes and alkynes in a more sustainable fashion. Noticeably, metal catalysed versions have shown great interest and efficiency. By contrast, the use of earth abundant transition metal based catalysts for such transformations is less reported, even if there is a growing interest during the last decade. This review article reports and highlights recent developments using manganese, iron, cobalt, nickel and copper based catalysts for hydro‐ and oxyphosphination, notably exhibiting the selectivity, functional group tolerance, milder conditions and catalyst design. Even if significant progresses were made, the scopes are still rather limited (mainly focused on activated olefins such as styrenes) and chemo‐ and stereo‐selectivity issues still have to be solved, notably for asymmetric transformations. Of interest, the use of visible light including blue one as activator emerged giving promising and stimulating results at ambient conditions.

Conversion of Methane at Room Temperature Mediated by the Ta-Ta σ-Bond.

Metal-metal bonds constitute an important type of reactive centers for chemical transformation; however, the availability of active metal-metal bonds being capable of converting methane under mild conditions, the holy grail in catalysis, remains a serious challenge. Herein, benefiting from the systematic investigation of 36 metal clusters of tantalum by using mass spectrometric experiments complemented with quantum chemical calculations, the dehydrogenation of methane at room temperature was successfully achieved by 18 cluster species featuring σ-bonding electrons localized in single naked Ta-Ta centers. In sharp contrast, the other 18 remaining clusters, either without naked Ta-Ta σ-bond or with σ-bonding electrons delocalized over multiple Ta-Ta centers only exhibit molecular CH4-adsorption reactivity or inertness. Mechanistic studies revealed that changing cluster geometric configurations and tuning the number of simple inorganic ligands (e.g., oxygen) could flexibly manipulate the presence or absence of such a reactive Ta-Ta σ-bond. The discovery of Ta-Ta σ-type bond being able to exhibit outstanding activity toward methane conversion not only overturns the traditional recognition that only the metal-metal π- or δ-bonds of early transition metals could participate in bond activation but also opens up a new access to design of promising metal catalysts with dual-atom as reactive sites for chemical transformations.

Advancing highly selective low-temperature ammonia oxidation: Hydrophobic silicalite-1 shell confining silver nanoparticles on Cu/ZSM-5 core

A judiciously devised core–shell NH3-SCO catalyst featuring a Cu/ZSM-5 core enveloped by an Ag/silicalite-1 shell (Cu/ZSM-5@Ag/S-1) was rationally constructed. Integrating the silicalite-1 shell effectively suppresses the migration of Ag into Cu/ZSM-5 core, conserving the active Cu2+ sites for the catalytical conversion of byproducts NOx. Concurrently, the shell averts the formation of positively charged Ag species, facilitating the generation of abundant Ag0 nanoparticles encapsulated in the S-1 shell. Comprehensive characterizations reveal abundant Ag0 species within the core–shell Cu/ZSM-5@Ag/S-1 catalyst, boosting O2 activation and NH3 dehydrogenation and thereby contributing to superior low-temperature activity in NH3-SCO reactions. Furthermore, the hydrophobic S-1 shell effectively reinforces the hydrothermal stability of the core–shell Cu/ZSM-5@Ag/S-1. DRIFTS coupled with DFT studies elucidate that the core–shell sample follows the imide mechanism, while the shell-free sample adheres to the hydrazine mechanism. This work advances our understanding of catalyst design and presents a promising solution with practical implications for ammonia oxidation processes.

Three-dimensional Ni foam supported Pt/NiFe LDH catalyst with enhanced oxygen activation for room-temperature formaldehyde oxidation

Room-temperature catalytic oxidation of formaldehyde (HCHO) has been extensively investigated due to its high efficiency, convenience, and environmental friendliness. Herein, nickel-iron layered double hydroxide (NiFe LDH) nanosheets were synthesized in-situ on a nickel foil (NF) using a facile one-step hydrothermal method, followed by the deposition of ultra-low content (0.069 wt%) of Pt nanoparticles through NaBH4 reduction. The resulting three-dimensional (3D) hierarchical Pt/NiFe-NF catalyst exhibited exceptional activity for the complete decomposition of formaldehyde to carbon dioxide (CO2) at room temperature (∼95 % conversion within 1 h), as well as remarkable cycling stability. The 3D porous structure of Pt/NiFe-NF provides fast transport channels for the diffusion of gas molecules, making the active catalyst surfaces more accessible. Moreover, abundant hydroxyl groups in NiFe LDH serve as adsorption centers for HCHO molecules to form dioxymethylene (DOM) and formate intermediates. Furthermore, electronic interactions between NiFe LDH and Pt enhance the adsorption and activation of O2 on Pt surfaces, leading to the complete decomposition of intermediates into non-toxic products. This work presents new insights into the design and preparation of Pt-based 3D hierarchical catalysts with surface-rich hydroxyl groups for the efficient removal of indoor HCHO.

Bionic Design of Iron-Doped MoSe2 Catalyst for Efficient Nitrogen Fixation.

The catalytic system of biological nitrogen fixation in nature primarily relies on the "MoFe cofactor" within nitrogenase enzymes. Inspired by this natural organic structure, we have designed a bionic inorganic counterpart, iron doped MoSe2, for the efficient electroreduction of dinitrogen to ammonia. The introduced Fe dopant significantly enhances nitrogen fixation activity of MoSe2. Furthermore, we constructed a heterostructure catalyst, the Fe-MoSe2/Mo2C with more versatile Mo valence states. The heterostructured electrocatalyst achieves an ammonia production rate of 3.38 μg h-1 cm-2, and a Faradaic efficiency of 30.8%, which is ~5 fold higher than that of pristine MoSe2. This study presents a novel approach for designing bionic nitrogen fixation electrocatalysts.

Surface Engineering of Noble Metal Nanocrystals for Selective Hydrogenation

The selective hydrogenation has attracted increasing attention to chemists for the production of value‐added products in chemical industry. Over the past several decades, substantial effort has been devoted to the design of catalyst for the selective hydrogenation of light alkynes and α, β‐unsaturated aldehydes, two classic cases for selective hydrogenation in chemical industry. Despite the great progress, it remains great challenges to achieve the selective hydrogenation because the desired products are generally thermodynamically unfavored. Here, we summarize the recent advances on selective hydrogenation using noble metal nanocrystals, with an emphasis on the surface engineering of noble metal nanocrystals for the selective hydrogenation of light alkynes and α, β‐unsaturated aldehydes. We will highlight the strategies for surface engineering, the advanced techniques for characterizations, as well as mechanism studies. We hope this review will promote chemists to develop efficient and robust catalysts for selective hydrogenation.