Selectivity In Heterogeneous Catalysis Research Articles

Effects of alloying palladium with gold in furfural hydrogenation:An in situ ATR-IR spectroscopy and density functional theory study

Furfural is a versatile platform molecule and a model compound to explore the key factors influencing activity and selectivity in heterogeneous catalysis. In this study, Pd and AuPd nanoparticles (average size 3.5–4 nm) were deposited on TiO2 by sol immobilization method and were evaluated for liquid-phase furfural hydrogenation. Alloying Au and Pd caused a decrease in activity, an enhancement in stability, and a change in selectivity, favouring the complete hydrogenation of furfural over the decarbonylation reaction. These variations in catalytic performance were elucidated by combining in situ attenuated total reflectance infrared spectroscopy and density functional theory studies.

Following the temperature-induced activation of carbon-supported trigonal Pd3 nanoclusters for catalysis

[Pd3(μ-Cl)(μ-PPh2)2(PPh3)3]Cl clusters activated at 150 °C are highly active and selective heterogeneous hydrogenation catalysts for alkynol semihydrogenation.

Strong Metal‐support Interactions in Photocatalysis: Fundamentals and Design Methods

AbstractEngineering the composition and geometry of metallic sites has become a popular manner to boost reaction rate and control reaction selectivity in heterogeneous catalysis. Many studies have been devoted to enhancing the stability of metallic nanoparticles during catalytic reactions by dispersion on metal oxide supports such as TiO2, CeO2 or Nb2O5. These supports not only modulate electronic properties and dispersion/stabilization of metallic nanoparticle but also influence catalytic selectivity, resulting in the so‐called “strong metal‐support interaction” (SMSI). In this minireview, we outlined the discovery and fundamentals of SMSI, as well as its extensive development over years. In addition, we summarized recent approaches developed to induce the construction of SMSI between different metal nanoparticles and metal oxide supports. Associated characterization microscopic and spectroscopic techniques were emphasized. Despite being a prevalent concept in catalysis, the number of studies on SMSI in heterogeneous photocatalysis has been even in limitation. Herein, we highlighted the beneficial effects of SMSI on boosting photocatalytic activity for CO2 reduction and H2 evolution reactions. In general, despite some controversial aspects of the SMSI, this concept offers wide opportunities ahead and encourages researchers to rethink the local active site localization and photocatalyst design.

Dynamic Behavior of Intermediate Adsorbates to Control Activity and Product Selectivity in Heterogeneous Catalysis: Methanol Decomposition on Pt/TiO2(110).

Dynamic behavior of intermediate adsorbates, such as diffusion, spillover, and reverse spillover, has a strong influence on the catalytic performance in oxide-supported metal catalysts. However, it is challenging to elucidate how the intermediate adsorbates move on the catalyst surface and find active sites to give the corresponding products. In this study, the effect of the dynamic behavior of methoxy intermediate on methanol decomposition on a Pt/TiO2(110) surface has been clarified by combination of scanning tunneling microscopy (STM), temperature-programmed desorption (TPD), and density functional theory (DFT) calculations. The methoxy intermediates were formed by the dissociative adsorption of methanol molecules on Pt nanoparticles at room temperature followed by spillover to the TiO2(110) support surface. TPD results showed that the methoxy intermediates were thermally decomposed at >350 K on the Pt sites to produce CO (dehydrogenation) and CH4 (C-O bond scission). A decrease of the Pt nanoparticle density lowered the activity for the decomposition reaction and increased the selectivity toward CH4, which indicates that the reaction is controlled by diffusion and reverse spillover of the methoxy intermediates. Time-lapse STM imaging and DFT calculations revealed that the methoxy intermediates migrate on the five-fold coordinated Ti (Ti5c) sites along the [001] or direction with the aid of hydrogen adatoms bonded to the bridging oxygens (Obr) and can move over the entire surface to seek and find active Pt sites. This work offers an in-depth understanding of the important role of intermediate adsorbate migration in the control of the catalytic performance in oxide-supported metal catalysts.

Achieving Theory-Experiment Parity for Activity and Selectivity in Heterogeneous Catalysis Using Microkinetic Modeling.

ConspectusMicrokinetic modeling based on density functional theory (DFT) energies plays an essential role in heterogeneous catalysis because it reveals the fundamental chemistry for catalytic reactions and bridges the microscopic understanding from theoretical calculations and experimental observations. Microkinetic modeling requires building a set of ordinary differential equations (ODEs) based on the calculation results of thermodynamic properties of adsorbates and kinetic parameters for the reaction elementary steps. Solving a microkinetic model can extract information on catalytic chemistry, including critical reaction intermediates, reaction pathways, the surface species distribution, activity, and selectivity, thus providing vital guidelines for altering catalysts.However, the quantitative reliability of traditional microkinetic models is often insufficient to conclusively extrapolate the mechanistic details of complex reaction systems. This can be attributed to several factors, the most important of which is the limitation of obtaining an accurate estimation of the energy inputs via traditional calculation methods. These limitations include the difficulty of using static DFT methods to calculate reaction energies of adsorption/desorption processes, often rate-controlling or selectivity-determining steps, and the inadequate consideration of surface coverage effects. In addition, the robust microkinetic software is rare, which also complicates the resolution of complex catalytic systems.In this Account, we review our recent works toward refining the predictions of microkinetic modeling in heterogeneous catalysis and achieving theory–experiment parity for activity and selectivity. First, we introduce CATKINAS, a microkinetic software developed in our group, and show how it disentangles the problem that traditional microkinetic software has and how it can now be applied to obtain kinetic results for more sophisticated reaction systems. Second, we describe a molecular dynamics method developed recently to obtain the free-energy changes for the adsorption/desorption process to fill in the missing energy inputs. Third, we show that a rigorous consideration of surface coverage effects is pivotal for building more realistic models and obtaining accurate kinetic results. Following a series of studies on acetylene hydrogenation reactions on Pd catalysts, we demonstrate how this new approach can provide an improved quantitative understanding of the mechanism, active site, and intrinsic structural sensitivity. Finally, we conclude with a brief outlook and the remaining challenges in this field.

Designing Sites in Heterogeneous Catalysis: Are We Reaching Selectivities Competitive With Those of Homogeneous Catalysts?

A critical review of different prominent nanotechnologies adapted to catalysis is provided, with focus on how they contribute to the improvement of selectivity in heterogeneous catalysis. Ways to modify catalytic sites range from the use of the reversible or irreversible adsorption of molecular modifiers to the immobilization or tethering of homogeneous catalysts and the development of well-defined catalytic sites on solid surfaces. The latter covers methods for the dispersion of single-atom sites within solid supports as well as the use of complex nanostructures, and it includes the post-modification of materials via processes such as silylation and atomic layer deposition. All these methodologies exhibit both advantages and limitations, but all offer new avenues for the design of catalysts for specific applications. Because of the high cost of most nanotechnologies and the fact that the resulting materials may exhibit limited thermal or chemical stability, they may be best aimed at improving the selective synthesis of high value-added chemicals, to be incorporated in organic synthesis schemes, but other applications are being explored as well to address problems in energy production, for instance, and to design greener chemical processes. The details of each of these approaches are discussed, and representative examples are provided. We conclude with some general remarks on the future of this field.

Tuning precise numbers of supported nickel clusters on graphdiyne for efficient CO2 electroreduction toward various multi-carbon products

Compared to single-atom catalysts, supported metal clusters can exhibit enhanced activity and designated selectivity in heterogeneous catalysis due to their unique geometric and electronic features. Herein, by means of comprehensive density functional theory (DFT) computations, we systematically investigated the potential of several Ni clusters supported on graphdiyne (Nix/GDY, x = 1–6) for CO2 reduction reaction (CO2RR). Our results revealed that, due to the strong interaction between Ni atoms and sp-hybridized C atoms, these supported Ni clusters on GDY exhibit high stabilities and excellent electronic properties. In particular, according to the computed free energy profiles for CO2RR on these Nix/GDY systems, the anchored Ni4 cluster was revealed to exhibit high CO2RR catalytic activity with a small limiting potential and moderate kinetic barrier for C–C coupling, and CH4, C2H5OH, and C3H7OH were identified as the main products, which can be attributed to its strong capacity for CO2 activation due to its unique configuration and excellent electronic properties. Thus, by carefully controlling the precise numbers of atoms in sub-nano clusters, the spatially confined Ni clusters can perform as promising CO2RR catalysts with high-efficiency and high-selectivity, which may provide a useful guidance to further develop novel and low-cost metal clusters-based catalysts for sustain CO2 conversion to valuable chemicals and fuels.

Silica-Encapsulated Intermetallic Nanoparticles for Highly Active and Selective Heterogeneous Catalysis

ConspectusIntermetallic nanoparticles (iNPs) have been the subject of many recent reports for their demonstrated applications as highly active and selective heterogeneous catalysts. As a subclass of alloys, intermetallic compounds possess ordered crystal structures and, therefore, well-defined atomic environments, unlike the solid solution of alloys whose atomic arrangements are random and locally unpredictable. Catalytically active iNPs typically contain a group 8–10 transition metals as the “active” metals. They usually also include an “inactive” metal that does not directly participate in the catalytic reaction but can significantly modify the active metal’s behavior. The choice of the inactive metal component can range across the periodic table.A few general challenges remain to design iNPs as heterogeneous catalysts with outstanding performance. Synthetically, the high surface energy of small nanoparticles is prone to their aggregation, while maximizing the surface-to-volume ratios is highly desired for efficient noble metal utilization. Additionally, even though the formation of bulk intermetallic compounds has been extensively studied, the formation of intermetallic phases at the nanoscale can behave differently. For example, the formation temperatures of iNPs are often drastically different from those predicted from the bulk phase diagrams. This behavior often leads to further challenges in the synthesis of iNPs.In addition to synthetic challenges, it is also critical to demonstrate the performance of iNPs in catalysis and establish the structure–property relationships. Instrumental and computational techniques often assist the understanding of catalytic properties. Due to the long-range order of intermetallic structure, various electron and X-ray techniques are often used to precisely determine the structure of iNPs. Structural modeling in density functional theory (DFT) calculation can also benefit from such ordered structures. These techniques have siginificantly improved the understanding of enhanced catalytic properties of iNPs in thermo-, electro-, and photocatalysis. Hydrogenation of furfural to furfuryl alcohol, for example, is a model reaction where PtSn iNPs show enhanced activity and chemoselectivity in hydrogenating C═O rather than C═C bonds. This superior catalytic performance can be correlated to the change in the geometric and electronic surface structure of the PtSn iNPs based on careful instrumental and computational characterizations. Additionally, intermetallic surfaces can be further modified by ligands or defects. While adding complexity to iNP systems, these modifiers provide additional control over their catalytic properties.In this Account, taking encapsulated iNPs in mesoporous silica as an example, we review the current strategies to develop iNPs as high-performance heterogeneous catalysts, with insights on the distinct formation behavior of iNPs compared to bulk intermetallic materials. We then highlight thermo- and electro-catalysis reactions to which these iNP catalysts are applied. We also discuss the unique pairwise hydrogenation reaction with parahydrogen catalyzed by iNPs. In this reaction, iNPs show unparalleled potential. We anticipate that this Account could foster additional interests in studying intermetallic catalysts and lay the foundation for their applications.

Cubic CuxZrO100-x as an efficient and selective catalyst for the oxidation of aromatics active methyl, alcohol, and amine groups

The local structure of a supported active metal plays a vital role in determining the desired product's selectivity in heterogeneous catalysis. Herein, we have developed a simple protocol for the synthesis of Cu doped on cubic ZrO2 mixed metal oxide catalysts and used it for the selective oxidation of various functional groups. The catalyst was synthesized by varying the wt.% of Cu (1–20%) on ZrO2 by co-precipitation, followed by hydrothermal treatment. The X-ray diffraction pattern of the catalysts confirmed the formation of the cubic phase of ZrO2, and the growth of CuO occurred along the (111) plane. The microscopy analysis revealed the uniform distribution of Cu on the ZrO2 surface, while XPS analysis confirmed the presence of copper in the +2 oxidation state. The synthesized catalyst with 2 wt% loading of Cu on ZrO2 showed excellent liquid-phase oxidation properties and gave good to best conversion of active methyl groups, alcohols, and amines with high selectivities to corresponding ketones, aldehydes, and amides, respectively, under milder reaction conditions. Furthermore, the synthesized catalyst showed a broader substrate scope for the various substituted active methyl groups, alcohols, and amines with good conversion and selectivity.

Tuning the selectivity of CO2 hydrogenation using ceramic hollow fiber catalytic modules

The unique structural features and advantageous pore distributions of alumina hollow fibers can be exploited to tune the selectivity in heterogeneous catalysis.

Controlling Catalytic Selectivity Mediated by Stabilization of Reactive Intermediates in Small-Pore Environments: A Study of Mn/TiO2 in the NH3-SCR Reaction

Controlling selectivity in heterogeneous catalysis is essential for designing processes that minimize the production of undesired byproducts. For example, TiO2-supported manganese oxide, a promisin...

Integration of Metal Single Atoms on Hierarchical Porous Nitrogen-Doped Carbon for Highly Efficient Hydrogenation of Large-Sized Molecules in the Pharmaceutical Industry.

Single-atom catalysts (SACs) often exhibit superior activity and selectivity in heterogeneous catalysis because of their maximized atom utilization and unique coordination environments. However, most reported studies about SACs in heterogeneous catalysis focus on model reactions with simple molecules. In addition, many reported single atoms are confined in microporous structures, hindering the mass transfer of molecules with large sizes, thus limiting their practical applications in industry. In this study, we report a molten salt-assisted method to synthesize metal single atoms anchored on a hierarchical porous nitrogen-doped carbon support (denoted as M1/h-NC, M includes Co, Fe, Ni, Mn, and Cu). Taking Co1/h-NC as an example, compared to the control sample which has Co single atoms being encapsulated in a microporous N-doped carbon support (denoted as Co1/m-NC), Co1/h-NC exhibits significantly higher catalytic activity in the selective hydrogenation of large-sized pharmaceutical molecules, such as nimodipine (calcium channel blocker) and 2-(3',4'-methylenedioxyphenylethyl)quinoline (antispasmodic natural alkaloid intermediate). The superior catalytic performance of Co1/h-NC is directly ascribed to the integration of the advantages of single-atom active sites and hierarchical mesoporous structure, which is beneficial for the mass transfer of molecules with large sizes and enables nearly all the Co single atoms to be accessible for catalytic reactions.

Role of Intermediate Dynamics in Controlling Hydrogenation Selectivity by Heterogeneous Catalysis.

Selectivity in heterogeneous catalysis is essential while being the most difficult parameters to obtain from theoretical simulations. Although theory holds the key for catalytic design, in the search of complex reaction networks, intermediates are considered static and different configurations for addition reactions are not considered. Here, we present the crucial role of intermediate dynamics to understand reaction selectivity of heterogeneous catalysts by studying the dynamic properties. The hydrogenation of two different intermediates hydroperoxide (OOH) and vinyl (HCCH2) is crucial to in the direct synthesis of water peroxide and alkyne semi-hydrogenation are taken as examples on the bare and alloyed surfaces. For them, the reaction network is studied by density functional theory coupled to molecular dynamics to present the role of rotations and how they affect paths for the addition of atomic hydrogen to lead to the products. In summary, the thermodynamic selectivity can be mapped to the dynamic control in the kinetics of the process.

Synthesis of platinum single-site centers through metal-ligand self-assembly on powdered metal oxide supports

Developing single-site metal catalysts has been regarded as a promising strategy to improve activity and selectivity in heterogeneous catalysis. Here, we report a metal-ligand self-assembly method to create Pt single-site centers on powdered oxide supports. Impregnating Pt and a ligand 3,6-di-2-pyridyl-1,2,4,5-tetrazine (DPTZ) simultaneously (one-step) creates Pt-DPTZ single-sites on powdered MgO, Al2O3, and CeO2. MgO has the most uniform single-sites due to a strong, non-competitive support-ligand interaction, and a support-metal interaction of appropriate strength. Pt(II) centers are stabilized between the N binding pockets of DPTZ, with minimal metallic nanoparticle formation. This system was characterized by XAS, XPS, TEM, XRD, and CO adsorption. Sequential impregnation of Pt and DPTZ (two-step) was also tested on Al2O3 and CeO2, but is not as effective as the one-step method due to limited Pt accessibility and mobility. These oxide-supported Pt-DPTZ single-sites were found to be effective catalysts in hydrosilylation reactions. This work demonstrates a metal-ligand self-assembly strategy to create metal single-site centers on high surface area catalyst supports.

Concerted Bimetallic Nanocluster Synthesis and Encapsulation via Induced Zeolite Framework Demetallation for Shape and Substrate Selective Heterogeneous Catalysis.

Bimetallic nanoparticle encapsulation in microporous zeolite crystals is a promising route for producing catalysts with unprecedented reaction selectivities. Herein, a novel synthetic approach was developed to produce PtZnx nanoclusters encapsulated inside zeolite micropores by introducing Pt2+ cations into a zincosilicate framework via ion exchange, and subsequent controlled demetallation and alloying with framework Zn. The resulting zeolites featured nanoclusters with sizes of approximately 1 nm, having an interatomic structure corresponding to a PtZnx alloy as confirmed by pair distribution function (PDF) analysis. These materials featured simultaneous shape and substrate specificity demonstrated by the selective production of p-chloroaniline from the competitive hydrogenation of p-chloronitrobenzene and 1,3-dimethyl-5-nitrobenzene.

Concerted Bimetallic Nanocluster Synthesis and Encapsulation via Induced Zeolite Framework Demetallation for Shape and Substrate Selective Heterogeneous Catalysis

AbstractBimetallic nanoparticle encapsulation in microporous zeolite crystals is a promising route for producing catalysts with unprecedented reaction selectivities. Herein, a novel synthetic approach was developed to produce PtZnx nanoclusters encapsulated inside zeolite micropores by introducing Pt2+ cations into a zincosilicate framework via ion exchange, and subsequent controlled demetallation and alloying with framework Zn. The resulting zeolites featured nanoclusters with sizes of approximately 1 nm, having an interatomic structure corresponding to a PtZnx alloy as confirmed by pair distribution function (PDF) analysis. These materials featured simultaneous shape and substrate specificity demonstrated by the selective production of p‐chloroaniline from the competitive hydrogenation of p‐chloronitrobenzene and 1,3‐dimethyl‐5‐nitrobenzene.

Nanoparticles@nanoscale metal-organic framework composites as highly efficient heterogeneous catalysts for size- and shape-selective reactions

Composites incorporating nanoparticles (NPs) within metal-organic frameworks (MOFs) find applications in many different fields. In particular, using MOF layers as molecular sieves built on the NPs could enable selectivity in heterogeneous catalysis. However, such composites typically exhibit low catalytic efficiency, due to the slow diffusion of the reactants in the long and narrow channels of the MOF shell. In order to improve the catalytic efficiency of these systems, here we report the fabrication of NPs incorporated in nanosized MOFs (NPs@nano-MOFs), obtained by reducing the size of the MOF crystals grown around the NPs. The crystal size of the composites was controlled by modulating the nucleation rate of the MOFs during the encapsulation of pre-synthesized and catalytically active NPs; in this way, NPs@MOF crystals smaller than 50 nm were synthesized and subsequently used as highly efficient catalysts. Due to the shorter path from the MOF surface to the active sites, the obtained Pt@nano-MOFs composites showed a higher conversion rate than their larger-sized counterparts in the synthesis of imines via cascade reaction of nitrobenzene and in the hydrogenation of olefins, while retaining the excellent size and shape selectivity associated with the molecular sieving effect of the MOF layer. The present strategy can also be applied to prepare other encapsulated nanostructures combining various types of NPs and nano-MOFs, thus highlighting the broad potential of this approach for developing optimized catalysts with high reactivity and selectivity.

Structure and Dynamics of Individual Diastereomeric Complexes on Platinum: Surface Studies Related to Heterogeneous Enantioselective Catalysis.

The modification of heterogeneous catalysts through the chemisorption of chiral molecules is a method to create catalytic sites for enantioselective surface reactions. The chiral molecule is called a chiral modifier by analogy to the terms chiral auxiliary or chiral ligand used in homogeneous asymmetric catalysis. While there has been progress in understanding how chirality transfer occurs, the intrinsic difficulties in determining enantioselective reaction mechanisms are compounded by the multisite nature of heterogeneous catalysts and by the challenges facing stereospecific surface analysis. However, molecular descriptions have now emerged that are sufficiently detailed to herald rapid advances in the area. The driving force for the development of heterogeneous enantioselective catalysts stems, at the minimum, from the practical advantages they might offer over their homogeneous counterparts in terms of process scalability and catalyst reusability. The broader rewards from their study lie in the insights gained on factors controlling selectivity in heterogeneous catalysis. Reactions on surfaces to produce a desired enantiomer in high excess are particularly challenging since at room temperature, barrier differences as low as ∼2 kcal/mol between pathways to R and S products are sufficient to yield an enantiomeric ratio (er) of 90:10. Such small energy differences are comparable to weak interadsorbate interaction energies and are much smaller than chemisorption or even most physisorption energies. In this Account, we describe combined experimental and theoretical surface studies of individual diastereomeric complexes formed between chiral modifiers and prochiral reactants on the Pt(111) surface. Our work is inspired by the catalysis literature on the enantioselective hydrogenation of activated ketones on cinchona-modified Pt catalysts. Using scanning tunneling microscopy (STM) measurements and density functional theory (DFT) calculations, we probe the structures and relative abundances of non-covalently bonded complexes formed between three representative prochiral molecules and (R)-(+)-1-(1-naphthyl)ethylamine ((R)-NEA). All three prochiral molecules, 2,2,2-trifluoroacetophenone (TFAP), ketopantolactone (KPL), and methyl 3,3,3-trifluoropyruvate (MTFP), are found to form multiple complexation configurations around the ethylamine group of chemisorbed (R)-NEA. The principal intermolecular interaction is NH···O H-bonding. In each case, submolecularly resolved STM images permit the determination of the prochiral ratio (pr), pro-R to pro-S, proper to specific locations around the ethylamine group. The overall pr observed in experiments on large ensembles of KPL-(R)-NEA complexes is close to the er reported in the literature for the hydrogenation of KPL to pantolactone on (R)-NEA-modified Pt catalysts at 1 bar H2. The results of independent DFT and STM studies are merged to determine the geometries of the most abundant complexation configurations. The structures reveal the hierarchy of chemisorption and sometimes multiple H-bonding interactions operating in complexes. In particular, privileged complexes formed by KPL and MTFP reveal the participation of secondary CH···O interactions in stereocontrol. State-specific STM measurements on individual TFAP-(R)-NEA complexes show that complexation states interconvert through processes including prochiral inversion. The state-specific information on structure, prochirality, dynamics, and energy barriers delivered by the combination of DFT and STM provides insight on how to design better chiral modifiers.

Fast 'Operando' electron nanotomography.

Electron tomography in transmission electron microscopy provides valuable three-dimensional structural, morphological and chemical information of condensed matter at nanoscale. Current image acquisitions require at least tens of minutes, which prohibits the analysis of nano-objects evolving rapidly such as under dynamic environmental conditions. Reducing the acquisition duration to tens of seconds or less permits to follow in 3D the same object during its evolution under varying temperatures and pressures. We report Operando Electron nanotomography using image series acquired in less than 230 seconds instead of typically 15 min in the best cases so far. The in situ calcination of silica zeolites encaging silver nanoparticles, a catalytic nanosystem of potential interest for, e.g., nuclear waste treatments or selective heterogeneous catalysis, was successfully studied. Kinetic environmental Operando 3D electron microscopy becomes possible, as well as real time observation of beam sensitive samples (polymers, biological objects) without prior preparation, which reduces their contrast and reactivity.

Non-Colloidal Nanocatalysts Fabricated Using Arc Plasma Deposition and Their Application in Heterogenous Catalysis and Photocatalysis

To understand technologically complex catalytic systems and to tailor both activity and selectivity in heterogeneous catalysis and photocatalysis, there is the challenge of bridging the materials gap that exists between two- and three-dimensional model catalytic systems and real catalysts, which are comprised of highly dispersed, oxide-supported metal nanoparticles. While colloid nanoparticles synthesized using wet chemistry have the potential for tuning size, shape, and composition, there are complexities related to the organic capping layers. Therefore, the development of new model catalysts without a capping layer is crucial. Coaxial vacuum arc plasma deposition (APD) is a method to fabricate non-colloidal nanocatalysts that has the potential for large-scale synthesis of nanocatalysts and, at the same time, allows for systematic investigation of intrinsic factors that affect catalytic activity. In this article, we describe the fabrication of catalytic nanoparticles using APD, and their application in heterogeneous catalysis and photocatalysis research. Direct vaporization of metallic materials to deposit active materials on two-dimensional or three-dimensional oxide supports has drawn considerable interest due to its simplicity, high reproducibility, and the possibility for large-scale production. We highlight recent studies on metal–support interactions, the effect of doping on the oxide, and hot electron-driven chemical reactions. In the case of photocatalysis, APD was used to fabricate metal nanoparticles on a hierarchically porous oxide; enhanced hydrogen evolution by doping and porosity was also demonstrated. Therefore, the materials gap in catalysis can be bridged by the potential for large-scale synthesis of a variety of catalysts using APD.