Energy Barrier For Dissociation Research Articles

Delocalizing Excitation for Highly‐Active Organic Photovoltaic Catalysts

AbstractLocalized excitation in traditional organic photocatalysts typically prevents the generation and extraction of photo‐induced free charge carriers, limiting their activity enhancement under illumination. Here, we enhance delocalized photoexcitation of small molecular photovoltaic catalysts by weakening their electron‐phonon coupling via rational fluoro‐substitution. The optimized 2FBP‐4F catalyst we develop here exhibits a minimized Huang–Rhys factor of 0.35 in solution, high dielectric constant and strong crystallization in the solid state. As a result, the energy barrier for exciton dissociation is decreased, and more importantly, polarons are unusually observed in 2FBP‐4F nanoparticles (NPs). With the increased hole transfer efficiency and prolonged charge carrier lifetime highly related to enhanced exciton delocalization, the PM6 : 2FBP‐4F heterojunction NPs at varied concentration exhibit much higher optimized photocatalytic activity (207.6–561.8 mmol h−1 g−1) for hydrogen evolution than the control PM6 : BP‐4F and PM6 : 2FBP‐6F NPs, as well as other reported photocatalysts under simulated solar light (AM 1.5G, 100 mW cm−2).

Charge Redistribution of Lattice-Mismatched Co─Cu3P Boosting pH-Universal Water/Seawater Hydrogen Evolution.

Practical applications of the hydrogen evolution reaction (HER) rely on the development of highly efficient, stable, and low-cost catalysts. Tuning the electronic structure, morphology, and architecture of catalysts is an important way to realize efficient and stable HER electrocatalysts. Herein, Co-doped Cu3P-based sugar-gourd structures (Co─Cu3P/CF) are prepared on copper foam as active electrocatalysts for hydrogen evolution. This hierarchical structure facilitates fast mass transport during electrocatalysis. Notably, the introduction of Co not only induces a charge redistribution but also leads to lattice-mismatch on the atomic scale, which creates defects and performs as additional active sites. Therefore, Co─Cu3P/CF requires an overpotential of only 81, 111, 185, and 230mV to reach currents of 50, 100, 500, and 1000mA cm-2 in alkaline media and remains stable after 10 000 CV cycles in a row and up to 110h i-t stability tests. In addition, it also shows excellent HER performance in water/seawater electrolytes of different pH values. Experimental and DFT show that the introduction of Co modulates the electronic and energy level structures of the catalyst, optimizes the adsorption and desorption behavior of the intermediate, reduces the water dissociation energy barrier during the reaction, accelerates the Volmer step reaction, and thus improves the HER performance.

Unravelling the anchoring effects of Hd-Graphene for lithium‑sulfur batteries: A first-principles calculation

For the widespread commercialization of lithium‑sulfur (LiS) batteries, the identification of anchoring materials capable of effectively mitigating the shuttle effect is of paramount importance. This study is centered around examining the adsorption characteristics of lithium polysulfides (S8 and Li2Sn, n = 1, 2, 4, 6, 8), as well as investigating the sulfur reduction reaction (SRR), and the decomposition mechanisms of Li2S on the pristine and defective Hd-Graphene monolayers. These investigations were carried out using first-principles calculations. The results reveal that the adsorption energies of polysulfides to the electrolytes (DOL and DME) are lower compared to that on the substrates. The moderate anchoring strength (0.8–2.0 eV) between polysulfides and the monolayer can effectively suppress the shuttle effect. Additionally, the Gibbs free energy barrier for SRR on the substrate is determined to be about 0.68 eV. The dissociation energy barrier of Li2S on Hd-Graphene is about 1.54 eV. Lower energy barriers indicate favorable reaction kinetics, leading to improved discharging and charging efficiency. Based on these findings, Hd-Graphene is predicted to be a promising anchoring material for LiS batteries.

Steric interaction of iridium sites towards efficient oxygen and hydrogen evolution

Transition metal materials that loaded with trace of Iridium (Ir) are widely accepted as effective catalysts for oxygen evolution (OER) and hydrogen evolution reaction (HER), in which the Ir atoms exposed on the surface can directly affect the electrocatalytic reaction. However, this neglects the Ir – Ir interaction of distinct locations, which may be benefit for the fine-tuning of electronic structure. Herein, we changed the locations (surface and inside) of Ir atoms in the cobalt oxide (Co3O4@NC), and investigated their alkaline OER and HER performances. Combined with X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS) and theoretical calculations, we infer that the steric interactions induced by the surface – internal Ir sites can weaken the Ir-O bond and optimize the adsorption of intermediates on catalyst surface with a negative shift of d-band center, enabling the surface-Ir sites with lower energy barrier for water dissociation and hydrogen adsorption for HER. Therefore, the as-prepared Irw-Co3O4@NC with surface − inside Ir distributions significantly improve the HER without degrading OER performance, with low overpotential of −173 / −71 mV for HER at −10 mA·cm−2 in 0.1 M KOH / 1.0 M KOH, and 244 / 249 mV at 10 mA·cm−2 for OER.

Electrochemical Generation of Te Vacancy Pairs in PtTe for Efficient Hydrogen Evolution.

Two-dimensional (2D) van der Waals materials are increasingly seen as potential catalysts due to their unique structures and unmatched properties. However, achieving precise synthesis of these remarkable materials and regulating their atomic and electronic structures at the most fundamental level to enhance their catalytic performance remain a significant challenge. In this study, we synthesized single-crystal bulk PtTe crystals via chemical vapor transport and subsequently produced atomically thin, large PtTe nanosheets (NSs) through electrochemical cathode intercalation. These NSs are characterized by a significant presence of Te vacancy pairs, leading to undercoordinated Pt atoms on their basal planes. Experimental and theoretical studies together reveal that Te vacancy pairs effectively optimize and enhance the electronic properties (such as charge distribution, density of states near the Fermi level, and d-band center) of the resultant undercoordinated Pt atoms. This optimization results in a significantly higher percentage of dangling O-H water, a decreased energy barrier for water dissociation, and an increased binding affinity of these Pt atoms to active hydrogen intermediates. Consequently, PtTe NSs featuring exposed and undercoordinated Pt atoms demonstrate outstanding electrocatalytic activity in hydrogen evolution reactions, significantly surpassing the performance of standard commercial Pt/C catalysts.

Delocalizing Excitation for Highly-Active Organic Photovoltaic Catalysts.

Localized excitation in traditional organic photocatalysts typically prevents the generation and extraction of photo-induced free charge carriers, limiting their activity enhancement under illumination. Here, we enhance delocalized photoexcitation of small molecular photovoltaic catalysts by weakening their electron-phonon coupling via rational fluoro-substitution. The optimized 2FBP-4F catalyst we develop here exhibits a minimized Huang-Rhys factor of 0.35 in solution, high dielectric constant and strong crystallization in the solid state. As a result, the energy barrier for exciton dissociation is decreased, and more importantly, polarons are unusually observed in 2FBP-4F nanoparticles (NPs). With the increased hole transfer efficiency and prolonged carrier lifetime highly related to enhanced exciton delocalization, the PM6:2FBP-4F heterojunction NPs at varied concentration exhibit much higher optimized photocatalytic activity (207.6~561.8 mmol h-1 g-1) for hydrogen evolution than the control PM6:BP-4F and PM6:2FBP-6F NPs, as well as other reported photocatalysts under simulated solar light (AM1.5G, 100 mW cm-2).

Regulation of the d-band center of metal–organic frameworks for energy-saving hydrogen generation coupled with selective glycerol oxidation

The hybrid electrolyzer coupled glycerol oxidation (GOR) with hydrogen evolution reaction (HER) is fascinating to simultaneously generate H2 and high value-added chemicals with low energy input, yet facing a challenge. Herein, Cu-based metal-organic frameworks (Cu-MOFs) are reported as model catalysts for both HER and GOR through doping of atomically dispersed precious and nonprecious metals. Remarkably, the HER activity of Ru-doped Cu-MOF outperformed a Pt/C catalyst, with its Faradaic efficiency for formate formation at 90% at a low potential of 1.40 V. Furthermore, the hybrid electrolyzer only needed 1.36 V to achieve 10 mA cm-2, 340 mV lower than that for splitting pure water. Theoretical calculations demonstrated that electronic interactions between the host and guest (doped) metals shifted downward the d-band centers (εd) of MOFs. This consequently lowered water adsorption and dissociation energy barriers and optimized hydrogen adsorption energy, leading to significantly enhanced HER activities. Meanwhile, the downshift of εd centers reduced energy barriers for rate-limiting step and the formation energy of OH*, synergistically enhancing the activity of MOFs for GOR. These findings offered an effective means for simultaneous productions of hydrogen fuel and high value-added chemicals using one hybrid electrolyzer with low energy input.

Fluorine Modification Promoted Water Dissociation into Atomic Hydrogen on a Copper Electrode for Efficient Neutral Nitrate Reduction and Ammonia Recovery.

Electrocatalytic nitrate reduction to ammonia (NITRR) offers an attractive solution for alleviating environmental concerns, yet in neutral media, it is challenging as a result of the reliance on the atomic hydrogen (H*) supply by breaking the stubborn HO-H bond (∼492 kJ/mol) of H2O. Herein, we demonstrate that fluorine modification on a Cu electrode (F-NFs/CF) favors the formation of an O-H···F hydrogen bond at the Cu-H2O interface, remarkably stretching the O-H bond of H2O from 0.98 to 1.01 Å and lowering the energy barrier of water dissociation into H* from 0.64 to 0.35 eV at neutral pH. As a benefit from these advantages, F-NFs/CF could rapidly reduce NO3- to NH3 with a rate constant of 0.055 min-1 and a NH3 selectivity of ∼100%, far higher than those (0.004 min-1 and 9.2%) of the Cu counterpart. More importantly, we constructed a flow-through coupled device consisting of a NITRR electrolyzer and a NH3 recovery unit, realizing 98.1% of total nitrogen removal with 99.3% of NH3 recovery and reducing the denitrification cost to $5.1/kg of N. This study offers an effective strategy to manipulate the generation of H* from water dissociation for efficient NO3--to-NH3 conversion and sheds light on the importance of surface modification on a Cu electrode toward electrochemical reactions.

Enhancing Ni/Co Activity by Neighboring Pt Atoms in NiCoP/MXene Electrocatalyst for Alkaline Hydrogen Evolution

AbstractDensity functional theory (DFT) calculations demonstrate neighboring Pt atoms can enhance the metal activity of NiCoP for hydrogen evolution reaction (HER). However, it remains a great challenge to link Pt and NiCoP. Herein, we introduced curvature of bowl‐like structure to construct Pt/NiCoP interface by adding a minimal 1 ‰‐molar‐ratio Pt. The as‐prepared sample only requires an overpotential of 26.5 and 181.6 mV to accordingly achieve the current density of 10 and 500 mA cm−2 in 1 M KOH. The water dissociation energy barrier (Ea) has a ~43 % decrease compared with NiCoP counterpart. It also shows an ultrahigh stability with a small degradation rate of 10.6 μV h−1 at harsh conditions (500 mA cm−2 and 50 °C) after 3000 hrs. X‐ray photoelectron spectroscopy (XPS), soft X‐ray absorption spectroscopy (sXAS), and X‐ray absorption fine structure (XAFS) verify the interface electron transfer lowers the valence state of Co/Ni and activates them. DFT calculations also confirm the catalytic transition step of NiCoP can change from Heyrovsky (2.71 eV) to Tafel step (0.51 eV) in the neighborhood of Pt, in accord with the result of the improved Hads at the interface disclosed by in situ electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM) tests.

Enhancing Ni/Co Activity by Neighboring Pt Atoms in NiCoP/MXene Electrocatalyst for Alkaline Hydrogen Evolution.

Density functional theory (DFT) calculations demonstrate neighboring Pt atoms can enhance the metal activity of NiCoP for hydrogen evolution reaction (HER). However, it remains a great challenge to link Pt and NiCoP. Herein, we introduced curvature of bowl-like structure to construct Pt/NiCoP interface by adding a minimal 1 ‰-molar-ratio Pt. The as-prepared sample only requires an overpotential of 26.5 and 181.6 mV to accordingly achieve the current density of 10 and 500 mA cm-2 in 1 M KOH. The water dissociation energy barrier (Ea) has a ~43 % decrease compared with NiCoP counterpart. It also shows an ultrahigh stability with a small degradation rate of 10.6 μV h-1 at harsh conditions (500 mA cm-2 and 50 °C) after 3000 hrs. X-ray photoelectron spectroscopy (XPS), soft X-ray absorption spectroscopy (sXAS), and X-ray absorption fine structure (XAFS) verify the interface electron transfer lowers the valence state of Co/Ni and activates them. DFT calculations also confirm the catalytic transition step of NiCoP can change from Heyrovsky (2.71 eV) to Tafel step (0.51 eV) in the neighborhood of Pt, in accord with the result of the improved Hads at the interface disclosed by in situ electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM) tests.

A Sustainable Route to Ruthenium Phosphide (RuP)/Ru Heterostructures with Electron-Shuttling of Interfacial Ru for Efficient Hydrogen Evolution.

Ruthenium (Ru) is a promising electrocatalyst for the hydrogen evolution reaction (HER), despite suffering from low activity in non-acidic conditions due to the high kinetic energy barrier of H2O dissociation. Herein, the synthesis of carbon nanosheet-supported RuP/Ru heterostructures (RuP/Ru@CNS) from a natural polysaccharide is reported and demonstrates its behavior as an effective HER electrocatalyst in non-acidic conditions. The RuP/Ru@CNS exhibits low overpotential (106mV at 200 mA·cm-2) in alkaline electrolyte, exceeding most reported Ru-based electrocatalysts. The electron shuttling between Ru atoms at the RuP/Ru interface results in a lowered energy barrier for H2O dissociation by electron-deficient Ru atoms in the pure Ru phase, as well as optimized H* adsorption of electron-gaining Ru atoms in the neighboring RuP. A low H* spillover energy barrier between Ru atoms at the RuP/Ru interface further boosts HER kinetics. This study demonstrates a sustainable method for the fabrication of efficient Ru-based electrocatalysts and provides a more detailed understanding of interface effects in HER catalysis.

Construction of heterogeneous interfaces for water activation and dissociation to synergistically boost overall water splitting

Construction of heterogeneous interfaces with dual active components to synergistically promote both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is an effective strategy for facilitating electrochemical water splitting, but the appropriate active component regulation via simple synthesis procedures is still challenging. Herein, the Co and Co2Mo3O8 active components are screened to construct effective heterogeneous interfaces and successfully integrated on Ni foam by thermal reduction of cobalt molybdate precursor. And this bifunctional electrode (Co/Co2Mo3O8/NF) required overpotentials of only 164 and 360 mV to drive the 100 mA cm−2 for HER and OER in alkaline media, respectively. Theoretical calculations showed that the electron transfer occurred from Co to Co2Mo3O8 at the interface, then the formed interfacial cobalt atoms with deficient electron were beneficial for water activation, and reduced energy barrier of water dissociation under the synergistic effect of Co2Mo3O8. Notably, the alkaline electrolyzer based on symmetric Co/Co2Mo3O8/NF electrodes generated 100 mA cm−2 at a voltage of only 1.75 V, surpassing commercially available precious-metal Pt/RuO2-based catalysts.

Degradation of SF6 by dielectric barrier discharge cooperating with TiO2 photocatalysis: Insights into the reaction mechanism

Research into the degradation and conversion of SF6 is important for environmental protection. Dielectric barrier discharge (DBD) technology is recognized as a reliable method for processing industrial waste gases, such as SF6. This research introduces a dual approach, combining DBD with TiO2 photocatalysis, to enhance SF6 degradation. When operating at 90 W, the degradation removal efficiency (DRE) of 2 % SF6 reaches 99.99 %. Moreover, the energy efficiency, measured as G50, reaches 10.25 g/(kW·h) for the combined DBD and TiO2 photocatalysis system, is, surpassing the efficiency of the standalone DBD system. The introduction of 0.5 % H2O enables complete SF6 degradation at a reduced input power (70 W). This synergy promotes the generation of a more easily processed product, SO2. Density functional theory (DFT) studies indicate that the availability of active sites on TiO2(101) is a crucial factor affecting the degradation efficiency. Specifically, the pre-adsorption of H2O on TiO2(101) surfaces facilitates the initial bond dissociation of SF6, while these surfaces strongly adsorb crucial intermediates, thereby enhancing the degradation of SF6. Additionally, the selectivity of the products was related to the dissociation energy barriers, and the pre-adsorption of H2O reduces these barriers for key intermediates, thereby improving SO2 selectivity. This study provides new insights into SF6 degradation and conversion using DBD combined with photocatalysis and provides inspiration for the conversion of other greenhouse gases (CO2, CH4, etc.).

Porous rod-like structured ternary nitride heterocatalyst Co3Mo3N/Ni3Mo3N for efficient and stable hydrogen evolution reaction

Heterostructure electrocatalysts have garnered widespread attention for effectively enhancing electrocatalytic activity. However, less attention has been paid to ternary nitride heterostructure catalysts for the hydrogen evolution reaction (HER), and their synthesis remains challenging. In this study, a Co3Mo3N/Ni3Mo3N heterostructure catalyst on nickel foam (NF) is designed and prepared via high-temperature nitridation of the heterostructured precursor. The resulting 1D/3D hierarchical structure electrode, featuring rich heterointerfaces, provides abundant active sites, enhancing mass transport and charge transfer. Experimental results reveal strong electronic interactions at the heterointerface, while density functional theory (DFT) calculations establish that Co3Mo3N/Ni3Mo3N possesses a lower water dissociation energy barrier and optimized hydrogen adsorption energy. Consequently, it demonstrates excellent HER performance, exhibiting low overpotentials of 36 mV in alkaline and 58 mV in neutral media at 10 mA cm−2. This study presents an innovative approach to designing ternary nitride heterostructure catalysts with enhanced HER activity, applicable to other heterostructure catalysts.

Compressed Ru skin on atomic-ordered hexagonal Ru-Ni enabling rapid Volmer-Tafel kinetics for efficient alkaline hydrogen evolution

Ru-based materials are promising electrocatalysts for hydrogen evolution reaction (HER) owing to their low-cost (one twenty-fifth of Pt) and similar Gibbs free energy of H* adsorption (ΔGH*) to that of Pt. However, the inadequate ability for the water dissociation of Ru catalysts is significantly impeding the water splitting efficiency. In this work, we demonstrate an atomically ordered hexagonal Ru-Ni alloy with compressive-strained Ru skin as a high-performance HER catalyst for significantly boosting the water dissociation. The Ordered Ru-Ni achieves an optimized catalytic activity for alkaline HER with a low overpotential of 23 mV at 10 mA cm−2, Tafel slope of 25.9 mV dec−1 and superior mass activity of 4.83 A mg−1Ru, which is 15.1 times higher than Ru/C. According to DFT calculations, the ordered RuNi core imposes homogeneous compressive strain on the Ru skin, resulting in an optimum binding energy towards H*/OH* intermediates on Ru active sites for rapid Tafel step kinetics. Moreover, the decreased H2O dissociation energy barrier of Ordered Ru-Ni suggests a promoted Volmer-Tafel kinetics is achieved, significantly boosting the overall HER efficiency. This work provides a practical avenue for surface strain engineering of Ru-based catalysts to promote the HER activity.

Remodeling the Electronic Structure of Metallic Nickel and Ruthenium via Alloying in a Molecular Template for Sustainable Hydrogen Evolution.

The reasonably constructed high-performance electrocatalyst is crucial to achieve sustainable electrocatalytic water splitting. Alloying is a prospective approach to effectively boost the activity of metal electrocatalysts. However, it is a difficult subject for the controllable synthesis of small alloying nanostructures with high dispersion and robustness, preventing further application of alloy catalysts. Herein, we propose a well-defined molecular template to fabricate a highly dispersed NiRu alloy with ultrasmall size. The catalyst presents superior alkaline hydrogen evolution reaction (HER) performance featuring an overpotential as low as 20.6 ± 0.9 mV at 10 mA·cm-2. Particularly, it can work steadily for long periods of time at industrial-grade current densities of 0.5 and 1.0 A·cm-2 merely demanding low overpotentials of 65.7 ± 2.1 and 127.3 ± 4.3 mV, respectively. Spectral experiments and theoretical calculations revealed that alloying can change the d-band center of both Ni and Ru by remodeling the electron distribution and then optimizing the adsorption of intermediates to decrease the water dissociation energy barrier. Our research not only demonstrates the tremendous potential of molecular templates in architecting highly active ultrafine nanoalloy but also deepens the understanding of water electrolysis mechanism on alloy catalysts.

Nickel and Iron‐Doped Biocarbon Catalysts for Reverse Water‐Gas Shift Reaction

AbstractBiocarbon catalysts for reverse water‐gas shift reaction (RWGS) were produced from pyrolyzed fern and willow impregnated with iron and nickel nitrates. This reaction can partake during Fischer‐Tropsch synthesis (FTS) by consuming CO2 and lowering both the H2/CO ratio and the efficiency in the production of fuels. RWGS has attracted much attention to widespread utilization of CO2 through the production of syngas. The catalysts were therefore tested in a fixed‐bed reactor at 400 °C as it is the maximal temperature for FTS and high RWGS. They showed high selectivity towards CO (>84 %) and fair conversion (<17 %) compared to rust (81 %, 30 %, respectively) and Fe‐impregnated alumina (100 %, 8 %). No loss in selectivity and conversion was observed for a longer residence time (288 h). Biomass inherent metals could provide reactive gas adsorption sites that improve conversion by dispersing electrons which reduces adsorption and dissociation energy barriers. K, Mg and Ca in fern biocarbon catalysts may be related to the higher CO2 uptake compared to willow catalysts. Electron deficient sites produced by reduction of biocarbon oxygen functional groups may facilitate CO2 uptake and activation. Ni‐impregnated fern‐based biocarbon showed the highest activity, due to the synergetic effect of the inherent metals, O vacancies and strong metal‐carbon interactions.

Frustrated Lewis Pairs on Zr Single Atoms Supported N‐Doped TiO2‐x Catalysts for Electrochemical Nitrate Reduction To Ammonia

AbstractThe electrochemical reduction of nitrates (NO3RR) for ammonia synthesis at room temperature holds immense potential. One key challenge is the adsorption and activation of NO3−, along with the provision of sufficient active hydrogen to accelerate the hydrogenation process. Here, the study prepares N‐doped TiO2‐x supported by Zr single atoms (Zr‐TiON) with rich oxygen vacancies (Ov), in which unsaturated Zr (Lewis acidic, LA) sites together with oxygen atoms around Ov (Lewis base, LB) form frustrated Lewis acid‐base pairs (FLPs). At −60 mA cm−2, NH3 Faradaic efficiency reaches 94.8%, corresponding to the production rate of 663.15 µmol h−1 mgcat−1. The yield rate is up to 26.16 mmol h−1mgcat−1 at −1 A cm−2 in flowing electrolyzer. Theoretical calculations and in situ spectroscopy analysis reveal that the interaction between LA and LB sites in FLPs plays a crucial role in facilitating adsorption and activation of electron‐rich NO3− and electron‐deficient *H. The presence of enhanced FLPs significantly reduces the energy barrier for H2O dissociation, lowering it to 0.20 eV, which facilitates subsequent hydrogenation reactions. The abundance of *H accelerates hydrogenation process, thereby enhancing the activity of NO3RR. This FLP design offers a promising approach for paving the way for the development of highly efficient NO3RR catalysts.

Tuning the adsorption of H2O, H2 and O2 molecules on diamond surfaces by B-doping

In this study, the fundamental interactions between the low Miller index (001), (110) and (111) B-doped diamond surfaces and H2O, H2 and O2 molecules, which are commonly present during growth, in ambient air and involved in electrochemical reactions, are investigated by means of ab initio simulations. The results are presented in close comparison with previous studies on undoped diamond surfaces to reveal the impact of B doping. It is demonstrated that the B dopant is preferably incorporated on the topmost carbon layer and enhances the adsorption of H2O by forming a dative bond with O. On the contrary in some cases, it seems to weaken the adsorption of O2, compared to the undoped diamond. Moreover, a noticeable displacement of the surface atoms attached to the fragment of the dissociated H2O and O2 molecules was observed, which can be associated to early stages of wear at the atomistic level. B doping was also found to reduce the energy barriers for water dissociation in most cases, with this effect being most pronounced in the C(111) surfaces. These qualitative and quantitative results aim to provide useful insights for the development of improved protective coatings and electrochemical devices.

Twinning Engineering of Platinum/Iridium Nanonets as Turing-Type Catalysts for Efficient Water Splitting.

The twin boundary, a common lattice plane of mirror-symmetric crystals, may have high reactivity due to special atomic coordination. However, twinning platinum and iridium nanocatalysts are grand challenges due to the high stacking fault energies that are nearly 1 order of magnitude larger than those of easy-twinning gold and silver. Here, we demonstrate that Turing structuring, realized by selective etching of superthin metal film, provides 14.3 and 18.9 times increases in twin-boundary densities for platinum and iridium nanonets, comparable to the highly twinned silver nanocatalysts. The Turing configurations with abundant low-coordination atoms contribute to the formation of nanotwins and create a large active surface area. Theoretical calculations reveal that the specific atom arrangement on the twin boundary changes the electronic structure and reduces the energy barrier of water dissociation. The optimal Turing-type platinum nanonets demonstrated excellent hydrogen-evolution-reaction performance with a 25.6 mV overpotential at 10.0 mA·cm-2 and a 14.8-fold increase in mass activity. And the bifunctional Turing iridium catalysts integrated in the water electrolyzer had a mass activity 23.0 times that of commercial iridium catalysts. This work opens a new avenue for nanocrystal twinning as a facile paradigm for designing high-performance nanocatalysts.