Rational Design Of Heterogeneous Catalysts Research Articles

Metal-support spin orders: Crucial effect on electrocatalytic oxygen reduction

Magnetic property (e.g. spin order) of support is of great importance in the rational design of heterogeneous catalysts. Herein, we have taken the Ni-supported ferromagnetic (FM) CrBr3 support (Nix/CrBr3) to thoroughly investigate the effect of spin-order on electrocatalytic oxygen reduction reaction (ORR) via spin-polarized density functional theory calculations. Specifically, Ni loading induces anti-FM coupling in Ni–Cr, leading to a transition from FM-to-ferrimagnetic (FIM) properties, while Ni–Ni metallic bonds create a robust FM direct exchange, benefiting the improvement of the phase transition temperature. Interestingly, with the increase in Ni loading, the easy magnetic axis changes from out-of-plane (2D-Heisenberg) to in-plane (2D-XY). The adsorption properties of Nix/CrBr3, involving O2 adsorption energy and configuration, are not governed by the d-band center but strongly correlate with magnetic anisotropy. It is noteworthy that the applied potential and electrolyte acidity triggers spin-order transition phenomena during the ORR and induces the catalytic pathway change from 4e− ORR to 2e− ORR with the excellent onset potential of 0.93 V/reversible hydrogen electrode, comparable to the existing most excellent noble-metal catalysts. Generally, these findings offer new avenues to understand and design heterogeneous catalysts with magnetic support.

Incorporation of atomic Fe-oxide triggers a quantum leap in the CO2 methanation performance of Ni-hydroxide

The heterogeneous catalytic conversion of carbon dioxide (CO2) to methane (CH4) via CO2 methanation offers a promising avenue for establishing the closed carbon loop. Nevertheless, the lack of effective catalysts limits its industrial applications. Considering this, we developed a novel heterogeneous catalyst comprising oxygen vacancies enriched atomic Fe-oxide clusters confined in the TiO2-supported Ni-hydroxide (denoted as NiFe-TiO2) via wet chemical reduction method. This material delivers an unprecedently high CH4 productivity of ∼24,358 mmol g-1h−1 in CO2 methanation at 300 °C, surpassing the Ni-TiO2 (12,481 mmol g-1h−1) by ∼ 95 %. On top of that, the high structural reliability of the Fe-oxide atomic clusters endows the NiFe-TiO2 catalyst with outstanding durability, where it achieves an optimum CH4 productivity of ∼ 36,399 mmol g-1h−1 after 116 cycles (155 h) with CH4 selectivity of 90.5 % and retains the pristine performance up to 220 cycles (330 h) in the stability test. With evidence from in-situ X-ray absorption and ambient pressure X-ray photoelectron spectroscopy studies, the performance descriptors and reaction pathways were unveiled, where the oxygen vacancies in the atomic Fe-oxide clusters and the adjacent Ni-hydroxide domains synergistically boost the CO2 activation and the H2 dissociation, respectively. Such a potential synergy enables the simultaneous operation of all intermediate steps for enhanced CO2 methanation kinetics on the NiFe-TiO2 surface. Most importantly, these findings not only unravel the merits of oxygen vacancies in transition metals for CO2 methanation but mark a step ahead for the rational design of heterogeneous catalysts in various catalytic applications.

A Coordination-Derived Cerium-Based Amorphous-Crystalline Heterostructure with High Electrocatalytic Oxygen Evolution Activity.

The rational design of heterogeneous catalysts is crucial for achieving optimal physicochemical properties and high electrochemical activity. However, the development of new amorphous-crystalline heterostructures is significantly more challenging than that of the existing crystalline-crystalline heterostructures. To overcome these issues, a coordination-assisted strategy that can help fabricate an amorphous NiO/crystalline NiCeOx (a-NiO/c-NiCeOx) heterostructure is reported herein. The coordination geometry of the organic ligands plays a pivotal role in permitting the formation of coordination polymers with high Ni contents. This consequently provides an opportunity for enabling the supersaturation of Ni in the NiCeOx structure during annealing, leading to the endogenous spillover of Ni from the depths of NiCeOx to its surface. The resulting heterostructure, featuring strongly coupled amorphous NiO and crystalline NiCeOx, exhibits harmonious interactions in addition to low overpotentials and high catalytic stability in the oxygen evolution reaction (OER). Theoretical calculations prove that the amorphous-crystalline interfaces facilitate charge transfer, which plays a critical role in regulating the local electron density of the Ni sites, thereby promoting the adsorption of oxygen-based intermediates on the Ni sites and lowering the dissociation-related energy barriers. Overall, this study underscores the potential of coordinating different metal ions at the molecular level to advance amorphous-crystalline heterostructure design.

Synergistic catalysis for promoting selective C-C/C-O cleavage in plastic waste: structure-activity relationship and rational design of heterogeneous catalysts for liquid hydrocarbon production.

Ever-increasing consumption of plastic products and poor waste management infrastructure have resulted in a massive accumulation of plastic waste in environments, causing adverse effects on climate and living organisms. Although contributing ∼10% towards the total plastic waste management infrastructure, the chemical recycling of plastic waste is considered a viable option to valorize plastic waste into platform chemicals and liquid fuels. Among the various chemical upcycling processes, catalytic hydroprocessing has attracted interest due to its potential to offer higher selectivity than other thermal-based approaches. Heterogeneous catalytic hydroprocessing reactions offer routes for converting plastic waste into essential industrially important molecules. However, the functional group similarities in the plastic polymers frequently constrain reaction selectivity. Therefore, a fundamental understanding of metal selection for targeted bond activation and plastic interaction on solid surfaces is essential for catalyst design and reaction engineering. In this review, we critically assess the structure-activity relationship of catalysts used in the hydroprocessing of plastic waste for the selective production of liquid hydrocarbons. We discuss the significance of C-C/C-O bond activation in plastic waste through active site modulation and surface modification to elucidate reaction networks and pathways for achieving selective bond activation and cleavage. Finally, we highlight current challenges and future opportunities in catalyst design to upcycle real-life plastic waste and produce selective liquid hydrocarbons.

Investigating Spillover Energy as a Descriptor for Single-Atom Alloy Catalyst Design.

The identification of thermodynamic descriptors of catalytic performance is essential for the rational design of heterogeneous catalysts. Here, we investigate how spillover energy, a descriptor quantifying whether intermediates are more stable at the dopant or host metal sites, can be used to design single-atom alloys (SAAs) for formic acid dehydrogenation. Using theoretical calculations, we identify NiCu as a SAA with favorable spillover energy and demonstrate that formate intermediates produced after the initial O-H activation are more stable at Ni sites where rate-determining C-H activation occurs. Surface science experiments demonstrated that NiCu(111) SAAs are more reactive than Cu(111) while they still follow the formate reaction pathway. However, reactor studies of silica-supported NiCu SAA nanoparticles showed only a modest improvement over Cu resulting from surface coverage effects. Overall, this study demonstrates the potential of engineering SAAs using spillover energy as a design parameter and highlights the importance of adsorbate-adsorbate interactions under steady-state operation.

Insights into boosting catalytic hydrogen evolution over Co doping Ru nanoparticles

Accurate regulation of surface chemical state on catalysts is crucial for achieving efficient performance but remains a major challenge. In this work, the lattice strain, d electronic state and ensemble effect of supported Ru catalysts are tuned via Co doping to boost the hydrogen evolution from ammonia borane (AB) hydrolysis. The optimized Ru0.6Co0.4/P25 composite displays outstanding catalytic performance with a turnover frequency of 443.7 min−1 in the absence of strong alkali. Experimental analysis and theoretical simulation reveal the boosting effect of RuCo alloy on the activation of AB originating from the compressed lattice strain, reduced d-band center of Ru via Co doping. The ensemble effect on optimized surface state leads to a bimolecular activation of H2O on Co atoms and AB on Ru atoms. Suitable adsorption strength of H* intermediates and reduced energy barrier of H2O dissociation induced by the electron interaction between Ru and Co atoms are responsible for the prominent catalytic activity over RuCo alloy. This research provides new insights into the catalytic mechanism and inspiration for the rational design of heterogeneous catalysts and energy storage materials.

Understanding the Source of Error in First-Principles-Based Micro-Kinetic Modeling: Density Functional Theory Calculations Versus the Mean-Field Approximation

First-principles-based micro-kinetic modeling has become an essential tool in the rational design of heterogeneous catalysts. Currently, most theoretical understandings and predictions are provided by this model, which combines results from density functional theory (DFT) calculations at the generalized gradient approximation level with the simulations using the mean-field micro-kinetic modeling (MF-MKM). In spite of its popularity and success in the catalyst design and screening, sometimes this combination yields undesired predictions that significantly deviate from experimental observations. It is, therefore, important to understand its success and failure and to locate the bottleneck of applying/improving the conventional MF-MKM. To this end, we have compared the errors that come from different DFT functionals with those introduced by the MF approximations against the kinetic Monte Carlo (KMC) results for the Pt-catalyzed water gas shift reaction system. It was found that the shape of the volcano map is less sensitive to the differences in the DFT functionals, even though their predictions of the key energetic parameters are distinctly different. On the other hand, the top of the volcano map, the detailed mechanism, as well as some key kinetic properties are markedly affected by the change of the energetic data. In comparison, the traditional MF-MKM that neglects the adsorbate–adsorbate interactions totally fails to describe the reaction kinetics. The inclusion of the adsorbate–adsorbate interaction effect can significantly improve the performance of the MF-MKM, which results in largely similar predictions to the reference data provided by KMC simulations. Nevertheless, the missing spatial correlation in the MF treatment can lead to an improper description in the high coverage region. Our analyses demonstrate that the accuracy of the MKM might not always be improved by only modifying the DFT-calculated energetic parameters, and close attention should be paid to the kinetic simulation method employed, particularly when quantitative kinetic properties are to be expected.

Elevated degradation of di-n‑butyl phthalate by activating peroxymonosulfate over GO[sbnd]CoFe2O4 composites: Synergistic effects and mechanisms

Rational design of heterogeneous catalysts with high activity and stability is crucial in peroxymonosulfate (PMS)-based oxidation treatment of wastewater. Herein, the graphite oxide-cobalt ferrite (GO-CoFe2O4) composite was constructed, and its morphological, component and structural characteristics were thoroughly examined, respectively. GO-CoFe2O4 obviously boosted PMS catalytic performance on di-n‑butyl phthalate removal (DBP, RDBP = 90%, RTOC = 37%), which indicated by the first-order kinetic constant (kDBP = 0.060 min−1) being roughly 4 times than pure CoFe2O4 (kDBP = 0.015 min−1). The fabrication of GO-CoFe2O4 brought the favorable stability and repeatability up to six cycles. Moreover, the method of batch dosing catalyst was creatively proposed to improve the PMS utilization efficiency. The coupling of GO enhanced the dispersion of CoFe2O4 particles to obtain sufficient active sites, additionally, the plentiful C=O groups and free-flowing electrons on GO promoted GO-CoFe2O4 to coordinate a redox process during PMS activation. With the aid of theoretical calculations, GO-CoFe2O4 was revealed to exhibit a strong affinity toward PMS adsorption, where PMS spontaneously dissociated into sulfate radical (SO4•−), hydroxyl radical (•OH) and singlet oxygen (1O2), acting as the reactive oxygen species (ROSs). Electrons cycling between Co, Fe and O species ensured continuous ROSs generation and excellent catalytic performance.

Probing the formation of soluble humins in catalytic dehydration of fructose to 5-hydroxymethylfurfural over HZSM-5 catalyst

Understanding the formation paths of humins and corresponding influencing factors in fructose dehydration catalyzed by a solid acid would be helpful for the rational design of heterogeneous catalysts for efficient synthesis of 5-hydroxymethylfurfural (HMF). In this work, the fructose-to-HMF dehydration has been studied over HZMS-5 with various Si/Al ratios to get insights into the evolution pathways of soluble humins (i.e., oligomeric products). It was found that three main representative paths were involved in the formation of soluble humins under the catalysis of HZMS-5 solid acids: 1) oligomer I formed through dehydrated condensation of fructose and/or HMF, 2) oligomer II formed through degradative (-FA) condensation of fructose and/or HMF, and 3) oligomer III formed from degradative (–HCHO) condensation of fructose and/or HMF. We demonstrated that the Brønsted acids with weak (i.e., Alpair) and medium-strong (i.e., Alpair) strengths on HZSM-5 along with those dissolved from Lewis acidic sites (i.e., Alsingle and Alq3) both contributed to the formation of oligomer I, the medium-strong Brønsted acids and strong Lewis acids on HZSM-5 were responsible for the formation of oligomer II, and the Brønsted acids with high acid density promoted the formation of oligomer III. HZSM-5 with a low density ratio between medium-strong and weak Brønsted acids (Dmedium-strong/Dweak = 0.74) along with a low density of strong Lewis acids was found to be effective for fructose-to-HMF dehydration by inhibiting humin formations to the maximum extent. This work highlighted the rational design of heterogeneous catalysts with moderate acid density and acid strength to comprehensively avoid the formation of undesired humins in HMF biorefinery.

Toward accurate and efficient dynamic computational strategy for heterogeneous catalysis: Temperature-dependent thermodynamics and kinetics for the chemisorbed on-surface CO

Computational tools on top of first principle calculations have played an indispensable role in revealing the molecular details, thermodynamics, and kinetics in catalytic reactions. Here we proposed a highly efficient dynamic strategy for the calculation of thermodynamic and kinetic properties in heterogeneous catalysis on the basis of efficient potential energy surface (PES) and MD simulations. Taking CO adsorbate on Ru(0001) surface as the illustrative model system, we demonstrated the PES-based MD can efficiently generate reliable two-dimensional potential-of-mean-force (PMF) surfaces in a wide range of temperatures, and thus temperature-dependent thermodynamic properties can be obtained in a comprehensive investigation on the whole PMF surface. Moreover, MD offers an effective way to describe the surface kinetics such as adsorbate on-surface movement, which goes beyond the most popular static approach based on free energy barrier and transition state theory (TST). We further revealed that the dynamic strategy significantly improves the predictions of both thermodynamic and kinetic properties as compared to the popular ideal statistic mechanics approaches such as harmonic analysis and TST. It is expected that this accurate yet efficient dynamic strategy can be powerful in understanding mechanisms and reactivity of a catalytic surface system, and further guides the rational design of heterogeneous catalysts.

Metal-organic frameworks enable regio- and stereo-selective functionalization of aldehydes and ketones

<h2>Summary</h2> Selective C–C bond establishment from plentiful carbonyl compounds, which represents a crucial route to get the value-added products, is still far from satisfying both academic and industrial needs. Here, confirmed by both experiment and theoretical calculation, we report versatile and efficient asymmetric cross-coupling between carbonyl radicals (from aldehydes) and aryl radicals (from aryl halides) by adopting porous chiral metal-organic frameworks (MOFs) as catalysts under light illumination. In addition, these MOFs work well in catalyzing secondary amine-mediated asymmetric β- and α-carbonyl arylation of saturated aldehydes and ketones, thanks to the switchable features of both photoabsorbing metal-nitrogen clusters and chiral organic ligands inside MOFs. This work opens the avenue toward the rational design of heterogeneous catalysts for precise regio- and stereo-selective syntheses.

Rational Functionalization of UiO-66 with Pd Nanoparticles: Synthesis and In Situ Fourier-Transform Infrared Monitoring.

Functionalization of metal-organic frameworks (MOFs) with noble metal nanoparticles (NPs) is a challenging task. Conventional impregnation by metals often leads to agglomerates on the surface of MOF crystals. Functional groups on linkers interact with metal precursors and promote the homogeneous distribution of NPs in the pores of MOFs, but their uncontrolled localization can block channels and thus hinder mass transport. To overcome this problem, we created nucleation centers only in the defective pores of the UiO-66 MOF via the postsynthesis exchange. First, we have introduced defects into UiO-66 using benzoic acid as a modulator. Second, the modulator was exchanged for amino-benzoic acid. As a result, amino groups have decorated mainly the defective pores and attracted the Pd precursor after impregnation. The interaction of the metal precursor with amino groups and the growth of NPs were monitored by in situ infrared spectroscopy. Three processes were distinguished: the gaseous HCl release, NH2 reactivation, and growth of extended Pd surfaces. Uniform Pd NPs were located in the pores because of the homogeneous distribution of the precursor and pore diffusion-limited nucleation rate. Our work demonstrates an alternative approach of controlled Pd incorporation into UiO-66 that is of great importance for the rational design of heterogeneous catalysts.

Effect of pore structure on Ni/Al2O3 microsphere catalysts for enhanced CO2 methanation

An understanding of the support effect is fundamental for guiding the rational design of heterogeneous catalysts. Herein, the role of pore structure on metal dispersion and catalytic performance was comprehensively investigated using Ni/Al2O3 catalysts. Three different Al2O3 supports, including Al2O3 microspheres prepared in microchannels and two commercially available Al2O3 supports named Sample 1 and Sample 2, were used and the Ni/Al2O3 catalysts were prepared by wetness impregnation method. X-ray diffraction, transmission electron microscopy, H2 temperature-programmed reduction, X-ray photoelectron spectroscopy, N2 adsorption–desorption, and H2 pulse chemisorption analyses combined with a sintering kinetic model were used to investigate the effect of the support pore structure. The narrow pore size distribution (3–15 nm) of Al2O3 microspheres and Sample 1 led to a uniform NiO dispersion for the calcined catalysts. Moreover, the high specific surface area (291 m2/g) and large pore volume (1.0 mL/g) of the Al2O3 microspheres were beneficial for the deposition of NiO particles inside mesopore to obtain a stronger metal–support interaction. Owing to the smaller NiO nanoparticles and stronger metal–support interaction, the reduced Ni/Al2O3 microspheres exhibited an average Ni particle size of 10.2 nm under 36 wt% nickel loading, whereas the average Ni particle size loaded on Sample 1 and Sample 2 were 12.6 nm and 13.2 nm, respectively. The optimized CO2 conversion of 87.0% at 300 °C under atmospheric pressure was attributed to the large pore volume and uniform Ni dispersion of Ni/Al2O3 microsphere catalysts while the same value for Sample 1 and Sample 2 catalysts was 81.5% and 55.0%, respectively. This work provides valuable guidelines for designing effective CO2 methanation support and proves the potential application of Al2O3 microspheres for CO2 methanation.

Photocatalytic reduction of low-concentration CO2 by metal-organic frameworks.

Direct conversion of diluted CO2 to value-added chemical stocks and fuels with solar energy is an energy-saving approach to relieve global warming and realize a carbon-neutral cycle. The exploration of catalysts with both efficient CO2 adsorption and reduction ability is significant to achieving this goal. Metal-organic frameworks (MOFs) are emerging in the field of low-concentration CO2 reduction due to their highly tunable structure, high porosity, abundant active sites and excellent CO2 adsorption capacity. This highlight outlines the advantages of MOFs for low-pressure CO2 adsorption and the strategies to improve the photocatalytic performance of MOF materials at low CO2 concentrations, including the functionalization of organic ligands, regulation of metal nodes and preparation of MOF composites or derivatives. This paper aims to provide possible avenues for the rational design and development of catalysts with the ability to reduce low-concentration CO2 efficiently for practical applications.

Combinatorial neutron imaging methods for hydrogenation catalysts.

Heterogeneous catalysts are materials with a complex structure at the atomic to mesoscopic scale, which depends on a variety of empirical parameters applied during preparation and processing. Although model systems clarified the general physical and chemical phenomena relevant to catalysis, such as hydrogen spillover, a rational design of heterogeneous catalysts is impeded by the sheer number of parameters. Combinatorial methods and high-throughput techniques have the potential of accelerating the development of optimal catalysts. We describe here a combinatorial approach based on hydrogen adsorption/absorption and hydrogen-deuterium exchange quantified by neutron imaging. The method coined CONI is capable of measuring more than 50 samples simultaneously. As a proof of concept, we study Pt catalyzed WO3 as an archetypal spillover system, and a Ni-catalyst supported on Al2O3 and SiO2. CONI is ideally suited to distinguish between irreversible surface adsorption and reversible bulk absorption, providing quantitative information. Concretely, CONI yields the number of reversibly adsorbed/absorbed hydrogen atoms in and on a great number of various catalysts in a single experiment.

Rational design of heterogeneous catalysts by breaking and rebuilding scaling relations

Various scaling relations have long been established in the field of heterogeneous catalysis, but the resultant volcano curves inherently limit the catalytic performance of catalyst candidates. On the other hand, it is still very challenging to develop universal descriptors that can be used in various types of catalysts and reaction systems. For these reasons, several strategies have recently been proposed to break and rebuild scaling relations to go beyond the top of volcanoes. In this review, some previously proposed descriptors have been briefly introduced. Then, the strategies for breaking known and establishing new and more generalized scaling relations in complex catalytic systems have been summarized. Finally, the application of machine-learning techniques in identifying universal descriptors for future computational design and high-throughput screening of heterogeneous catalysts has been discussed.

Sinter Resistance and Activity Enhancement via a Facet-Dependent Metal–Support Interaction of Pd/ZnO Catalysts in CO Oxidation

Metal–support interaction (MSI) has been extensively investigated regarding its structural and catalytic modification in heterogeneous catalysts. Herein, we reveal how facet-dependent MSI impacts on the structure and performance of Pd/ZnO in the CO oxidation reaction. ZnO nanosheets with orthohexagonal shape which are exposed mainly with {001} facets exhibit remarkable thermal stability under air atmosphere until 600 °C, while ZnO nanorods bounded with {100} facets transform at 400 °C and totally change after calcination at 600 °C. Thus, the Pd species supported on ZnO nanorods and nanosheets also display different sintering behaviors after thermal treatment, and the particle size of Pd grows from 1.1 to 5.7 nm on {100} facets while it keeps high-dispersion on {001} facets after 600 °C calcination. In situ transmission electron microscopy was used to visualize the sintering process, demonstrating that Pd displays the Ostwald ripening and particle migration coalescence mechanism on ZnO {100} facets, while shows extraordinary stability on ZnO {001} facets. Therefore, Pd supported on ZnO nanorod exhibits deactivation behavior after high temperature treatment in CO oxidation, during which the T50 delays from 106 to 120 and 145 °C after 200, 400, and 600 °C calcination. Interestingly, Pd on ZnO nanosheet shows obvious activity enhancement from 137 to 90 and 75 °C of T50 after the same treatment, which is ascribed to the synergy between Pd and ZnO {001} facets during catalysis. This work gives in-depth understanding of the facet-dependent MSI of Pd/ZnO catalysts, and it sheds light on the rational design of heterogeneous catalysts with high efficiency and sinter resistance.

Dynamic Modification of Palladium Catalysts with Chain Alkylamines for the Selective Hydrogenation of Alkynes.

Selective hydrogenation of alkynes plays a pivotal role in the field of chemical production but still suffers from restrained catalytic activity and low alkene selectivity. Herein, a dynamic modification strategy was utilized by preferentially attaching diethylenetriamine (DETA) to the surface of the support to modify the Pd catalyst. The DETA-modified Pd catalyst demonstrates unprecedented reactivity (14,412 h-1) and selectivity as high as 94% for the semihydrogenation of 2-methyl-3-butyn-2-ol at 35 °C, presenting a 36-fold higher reactivity than the Lindlar catalyst. Moreover, the yield exceeds 98.2% at full conversion under no solvent and organic adsorbate conditions, indicating the potential applications for industrial production. Systematic studies reveal that flexible DETA serves in a reversible "breathing pattern" for the molecular discrimination by constructing dynamic metal-support interaction (DMSI), enabling selective exclusion of alkenes from the Pd surface. DETA is competent to dynamically adjust the adsorption behaviors of reactants and effectively boost the intrinsic activity of the modified catalyst. Impressively, the DETA-modified Pd catalyst exhibits exceptional stability even after being recycled 20 times. This work sheds light on a novel and applicable method for the rational design of heterogeneous catalysts via DMSI.

A rich catalog of C\u2013C bonded species formed in CO2 reduction on a plasmonic photocatalyst

The understanding and rational design of heterogeneous catalysts for complex reactions, such as CO2 reduction, requires knowledge of elementary steps and chemical species prevalent on the catalyst surface under operating conditions. Using in situ nanoscale surface-enhanced Raman scattering, we probe the surface of a Ag nanoparticle during plasmon-excitation-driven CO2 reduction in water. Enabled by the high spatiotemporal resolution and surface sensitivity of our method, we detect a rich array of C1–C4 species formed on the photocatalytically active surface. The abundance of multi-carbon compounds, such as butanol, suggests the favorability of kinetically challenging C–C coupling on the photoexcited Ag surface. Another advance of this work is the use of isotope labeling in nanoscale probing, which allows confirmation that detected species are the intermediates and products of the catalytic reaction rather than spurious contaminants. The surface chemical knowledge made accessible by our approach will inform the modeling and engineering of catalysts.

Engineering Nanoscale Metal‐Organic Frameworks for Heterogeneous Catalysis

Metal‐organic frameworks (MOFs) are porous crystalline materials composed of metal ions (or clusters) and organic ligands. Targeted preparation of nanoscale MOFs has been successfully achieved through numerous synthetic methods and is beneficial to improve the utilization of catalytic sites. On one hand, the dynamic bonds and rich selection of both metal centers and organic molecules enable broadening the types and functions of MOFs, thus offering the basis for rational design of heterogeneous catalysts at the molecular level. On the other hand, the reversible nature of connections between metal centers and organic ligands brings serious challenges about its stability under harsh reaction conditions. To optimize the catalytic performance of MOFs, considerable efforts have been devoted to tune the chemical environment of active sites by introducing electronic or channel confinement effect as well as controlling their size growth at nanoscale for increasing the surface coordination unsaturated sites. In this review, the state‐of‐the‐art development of nanoscale MOFs is summarized and particular focus is placed on regulation strategies of catalytic sites. The authors also propose the current challenges, the problems awaiting to be solved and opportunities in the future.