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Metal single‐atom catalysts represent one of the most promising non‐noble metal catalysts for the oxygen reduction reaction (ORR). However, they still suffer from insufficient activity and, particularly, durability for practical applications. Leveraging density functional theory (DFT) and machine learning (ML), we unravel an unexpected collective effect between FeN4OH sites, CeN4OH motifs, Fe nanoparticles (NPs), and Fe−CeO2 NPs. The collective effect comprises differently‐weighted electronic and geometric interactions, whitch results in significantly enhanced ORR activity for FeN4OH active sites with a half‐wave potential (E1/2) of 0.948 V versus the reversible hydrogen electrode (VRHE) in alkaline, relative to a commercial Pt/C (E1/2, 0.851 VRHE). Meanwhile, this collective effect endows the shortened Fe−N bonds and the remarkable durability with negligible activity loss after 50,000 potential cycles. The ML was used to understand the intricate geometric and electronic interactions in collective effect and reveal the intrinsic descriptors to account for the enhanced ORR performance. The universality of collective effect was demonstrated effective for the Co, Ni, Cu, Cr, and Mn‐based multicomponent ensembles. These results confirm the importance of collective effect to simultaneously improve catalytic activity and durability. [ABSTRACT FROM AUTHOR]

The oxygen evolution reaction (OER) over a family of metal-doped rutile IrO2 catalysts is theoretically investigated by controlling the species and position of doped elements. The subsurface substitution doping is demonstrated to efficiently regulate the eg-filling of surface iridium sites and lower the adsorption strength of oxygen intermediates, improving the catalytic activity for the OER. Finally, based on screening, subsurface Cu- and Li-doped IrO2 models stand near the top of the volcano plot and display high levels of structural stability toward acidic OER. [ABSTRACT FROM AUTHOR]

Electrocatalysis plays a fundamental role in many fields, such as metallurgy, medicine, chemical industry, and energy conversion. Anchoring active electrocatalysts with controllable loading and uniform dispersion onto suitable supports has become an attractive topic. This is because the supports can not only have the potential to improve catalytic activity and stability through the interaction between support and catalytic center, but also can reduce precious metal consumption by improving atomic utilization. Herein, recent theoretical and experimental progresses concerning the development of supports to anchor electrocatalytic materials are first reviewed. Next, their controllable syntheses, characterization techniques, metal‐support electronic interactions, and structure‐performance relationships are presented. Some representative carbon supports and non‐carbonaceous supports, as well as recently reported star supports such as 2D supports, single atom catalysts, and self‐supported catalysts are also summarized. In addition, the significant role of support in stabilizing and regulating catalytic active sites is particularly emphasized. Finally, challenges, opportunities, key problems, and further promising solutions for supported catalysts are proposed. [ABSTRACT FROM AUTHOR]

Orbital hybridization to regulate the electronic structures and surface chemisorption properties of transition metals has been extensively investigated for searching high-performance catalysts toward various reactions. Unlike conventional d–d hybridization, the d–sp hybridization interaction between transition metals and p-block elements could result in surprising electronic properties and catalytic activities. This feature article highlights the recent progress in the development of high-performance transition metal-based catalysts through the extraordinary d–sp hybridization strategy, particularly for energy-related electrocatalytic applications. We start by giving an introduction of fundamental concepts associated with electronic structures of transition metal catalysts, including the Sabatier principle, d-band theory, electronic descriptor, as well as the comparison of d–d hybridization and d–sp hybridization strategies. Then, we summarize the theoretical and experimental advances in d–sp hybridization catalysts, including p-block element-doped metal catalysts, intermetallic catalysts and supported metal catalysts, with emphasis on the important roles of d–sp hybridization in tuning catalytic performances. Finally, we present existing challenges and future development prospects for the rational design of advanced d–sp hybridization catalysts. [ABSTRACT FROM AUTHOR]

The development of earth‐abundant oxygen reduction reaction (ORR) catalysts with high catalytic activity and good stability for practical metal‐air batteries remains an enormous challenge. Herein, a highly efficient and durable ORR catalyst is reported, which consists of atomically dispersed Co single atoms (Co‐SAs) in the form of Co‐N4 moieties and small Co nanoparticles (Co‐SNPs) co‐anchored on nitrogen‐doped porous carbon nanocage (Co‐SAs/SNPs@NC). Benefiting from the synergistic effect of Co‐SAs and Co‐SNPs as well as the enhanced anticorrosion capability of the carbon matrix brought by its improved graphitization degree, the resultant Co‐SAs/SNPs@NC catalyst exhibits outstanding ORR activity and remarkable stability in alkaline media, outperforming Co‐SAs‐based catalyst (Co‐SAs@NC), and benchmark Pt/C catalyst. Density functional theory calculations reveal that the strong interaction between Co‐SNPs and Co‐N4 sites can increase the valence state of the active Co atoms in Co‐SAs/SNPs@NC and moderate the adsorption free energy of ORR intermediates, thus facilitating the reduction of O2. Moreover, the practical zinc‐air battery assembled with Co‐SAs/SNPs@NC catalyst demonstrates a maximum power density of 223.5 mW cm–2, a high specific capacity of 742 W h kg–1 at 50 mA cm–2 and a superior cycling stability. [ABSTRACT FROM AUTHOR]

The realization of seawater electrolysis requires high‐performing anode materials that should possess good catalytic activity, stability, and specificity for the oxygen evolution reaction (OER) as well as high resistance toward chloride corrosion. Herein, the design of a multilayered oxygen‐evolution electrode is reported to meet the multiple needs of anode material for saline water splitting. The multilayered electrode is synthesized through direct thermal boronization of commercially available NiFe alloy plate with boron powder, followed by electrochemical oxidation. And this electrode is composed of the surface oxidized NiFeBx alloy layer, the NiFeBx alloy interlayer, and the NiFe alloy substrate. The boron species are present in the form of metaborate in the outermost oxidized NiFeBx layer, and their existence is conductive to the generation and stabilization of the catalytic active phase γ‐(Ni,Fe)OOH. The introduction of NiFeBx interlayer effectively prevents the excessive oxidative corrosion of the anode material in the electrolyte containing chloride ions. [ABSTRACT FROM AUTHOR]

Reducing the amount of iridium in oxygen evolution electrocatalysts without compromising their catalytic performances is one of the major requirements in proton‐exchange‐membrane water electrolyzers. Herein, with the help of theoretical studies, we show that anatase‐type TiO2‐IrO2 solid solutions possess more active iridium catalytic sites for the oxygen evolution reaction (OER) than IrO2, the benchmark OER catalyst. Note that the same is not observed for their rutile‐type counterparts. However, owing to their thermodynamic metastability, anatase‐type TiO2‐IrO2 solid solutions are generally hard to synthesize. Our theoretical studies demonstrate that such catalytically active anatase‐type solid‐solution phases can be created in situ on the surfaces of readily available SrTiO3‐SrIrO3 solid solutions during electrocatalysis in acidic solution as the solution can etch away Sr atoms. We experimentally show this with porous SrTiO3‐SrIrO3 solid‐solution nanotubes synthesized by a facile synthetic route that contain 56 % less iridium than IrO2 yet show an order of magnitude higher apparent catalytic activity for OER in acidic solution. [ABSTRACT FROM AUTHOR]

A theoretical and experimental study gives insights into the nature of the metal–boron electronic interaction in boron‐bearing intermetallics and its effects on surface hydrogen adsorption and hydrogen‐evolving catalytic activity. Strong hybridization between the d orbitals of transition metal (TM) and the sp orbitals of boron exists in a family of fifteen TM–boron intermatallics (TM:B=1:1), and hydrogen atoms adsorb more weakly to the metal‐terminated intermetallic surfaces than to the corresponding pure metal surfaces. This modulation of electronic structure makes several intermetallics (e.g. PdB, RuB, ReB) prospective, efficient hydrogen‐evolving materials with catalytic activity close to Pt. A general reaction pathway towards the synthesis of such TMB intermetallics is provided; a class of seven phase‐pure TMB intermetallics, containing V, Nb, Ta, Cr, Mo, W, and Ru, are thus synthesized. RuB is a high‐performing, non‐platinum electrocatalyst for the hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

Simultaneous realization of improved activity, enhanced stability, and reduced cost remains a desirable yet challenging goal in the search of oxygen evolution electrocatalysts in acid. Herein we report iridium‐containing strontium titanates (Ir‐STO) as active and stable, low‐iridium perovskite electrocatalysts for the oxygen evolution reaction (OER) in acid. The Ir‐STO contains 57 wt % less iridium relative to the benchmark catalyst IrO2, but it exhibits more than 10 times higher catalytic activity for OER. It is shown to be among the most efficient iridium‐based oxide electrocatalysts for OER in acid. Theoretical results reveal that the incorporation of iridium dopants in the STO matrix activates the intrinsically inert titanium sites, strengthening the surface oxygen adsorption on titanium sites and thereby giving nonprecious titanium catalytic sites that have activities close to or even better than iridium sites. [ABSTRACT FROM AUTHOR]

Semiconductor electrodes integrated with cocatalysts are key components of photoelectrochemistry (PEC)‐based solar‐energy conversion. However, efforts to optimize the PEC device have been limited by an inadequate understanding of the interface interactions between the semiconductor–cocatalyst (sem|cat) and cocatalyst–electrolyte (cat|ele) interface. In our work, we used ferrihydrite (Fh)‐modified Ti–Fe2O3 as a model to explore the transfer process of photogenerated charge carriers between the Ti–Fe2O3–Fh (Ti–Fe2O3|Fh) interface and Fh‐electrolyte (Fh|ele) interface. The results demonstrate that the biphasic structure (Fh/Ti–Fe2O3) possesses the advantage that the minority hole transfer from Ti–Fe2O3 to Fh is driven by the interfacial electric field at the Ti–Fe2O3|Fh interface; meanwhile, the holes reached at the surface of Fh can rapidly inject into the electrolyte across the Fh|ele interface. As a benefit from the improved charge transfer at the Ti–Fe2O3|Fh and Fh|ele interface, the photocurrent density obtained by Fh/Ti–Fe2O3 can reach 2.32 mA cm−2 at 1.23 V versus RHE, which is three times higher than that of Ti–Fe2O3. Water splitting: The excellent performance of ferrihydrite (Fh)/Ti–Fe2O3 is attributed to the unhindered charge transfer at the Ti–Fe2O3|Fh and Fh|electrolyte interfaces. As a benefit from this improved charge transfer, the photocurrent density obtained by Fh/Ti–Fe2O3 can reach 2.32 mA cm−2 at 1.23 V versus the reversible hydrogen electrode, which is three times higher than that of Ti–Fe2O3. [ABSTRACT FROM AUTHOR]

Despite being technically possible, splitting water to generate hydrogen is still practically unfeasible due mainly to the lack of sustainable and efficient catalysts for the half reactions involved. Herein we report the synthesis of cobalt-embedded nitrogen-rich carbon nanotubes (NRCNTs) that 1) can efficiently electrocatalyze the hydrogen evolution reaction (HER) with activities close to that of Pt and 2) function well under acidic, neutral or basic media alike, allowing them to be coupled with the best available oxygen-evolving catalysts-which also play crucial roles in the overall water-splitting reaction. The materials are synthesized by a simple, easily scalable synthetic route involving thermal treatment of Co2+-embedded graphitic carbon nitride derived from inexpensive starting materials (dicyandiamide and CoCl2). The materials' efficient catalytic activity is mainly attributed to their nitrogen dopants and concomitant structural defects. [ABSTRACT FROM AUTHOR]

Understanding of catalytic trends is an important prerequisite for providing rational guidance toward the prediction of advanced catalysts as well as the development of original materials design principles. A combined theoretical and experimental study that reveals the periodic trends in electrocatalytic activity for the hydrogen evolution reaction (HER) from Group IV B to Group VIII metal diborides is reported here. Theoretical results demonstrate a general linear relationship between the catalytic activity and d‐band center of metal diboride, meaning that the latter can serve as a descriptor of activity. And theoretical results also predict ruthenium diboride as the most competitive, nonplatinum candidate among metal diborides for HER because this material has a suitable d‐band center and a high density of efficient active sites. Furthermore, the experimental results validate the theoretical activity trends and identify ruthenium diboride as an efficient, pH‐universal electrocatalyst with Pt‐like activity for HER under both acidic and alkaline media. A combined theoretical and experimental study is conducted to reveal the trends in electrocatalytic activity for the hydrogen evolution reaction (HER) on a family of 12 transition metal diborides. The results identify ruthenium diboride as an efficient, pH‐universal electrocatalyst with Pt‐like activity for HER under both acidic and alkaline media. [ABSTRACT FROM AUTHOR]

Monitoring trace formaldehyde gas in air is of critical importance because of its high toxicity and threat to health, which is rather difficult at ppb level, especially at high humidity. Here, Pt-doped In 2 O 3 composites consist of nanosheets with excellent formaldehyde sensing performance were prepared by a two-step method. The as-prepared 1 at% Pt-In 2 O 3 composites give the best sensing performance toward formaldehyde gas with higher response, better selectivity and short response-recovery time at a low operating temperature (120 °C) compared to the pure In 2 O 3 . Its response is about 3 times as large as that of pure In 2 O 3 to 10 ppm formaldehyde at 120 °C. The response time of the 1 at% Pt-In 2 O 3 composite is less than 2 s and its recovery time is 51 s. In particular, it can detect down to 60 ppb formaldehyde in a wide range of relative humidity (25%–90% RH). The enhanced sensing properties of the composites should be attributed to the high catalytic activity of Pt/PtO 2 nanoparticles decorated on the surface of In 2 O 3 hollow microspheres and the Schottky barrier between Pt species and In 2 O 3 . [ABSTRACT FROM AUTHOR]

Great efforts have been devoted on the detection of the volatile organic compounds indoor for human health. The detection of formaldehyde is one of the most important and popular issues for the wide usage of formaldehyde and its toxic. However, it is a challenge to monitor trace gaseous formaldehyde at lower working temperature. Herein, we present a sensor with a significantly improved sensing response and dramatically decreased operating temperature based on porous PtO 2 /SnO 2 microspheres. And the PtO 2 /SnO 2 -5 mol% composite shows the most outstanding sensing performance among all products. What’s more, the above sensor can detect gaseous formaldehyde in the ppb level (100 ppb) at low operating temperature (100 °C). The excellent sensing performance should be attributed to the high catalytic activity of PtO 2 nanoparticles decorated on the surface of SnO 2 microspheres and the porosity of the composite. [ABSTRACT FROM AUTHOR]

NiFe-based electrode materials exhibit great promise for next-generation efficient oxygen evolution reaction (OER) electrocatalysts in alkaline medium, but they are difficult to be scaled up for large-area fabrication and are lack of robust research under real industrial conditions. Here we present a rapid, room-temperature sulfuration strategy that transforms stainless steel meshes into highly active and stable oxygen evolution electrodes. Such method is easy to be scaled up to produce square meter-sized stainless steel electrodes (1 m × 1 m) with NiFeCr-containing trimetal sulfides on the surface. In a standard three-electrode cell, the sulfurated stainless steel electrode exhibits 7.2 times higher OER activity than the corresponding stainless steel, and possesses remarkable catalytic stability for over 1000 h at the current density range of 100–200 mA cm−2. During the OER, the Cr and S species are demonstrated to be easily detached from the electrode surface, and the in situ formed γ -(Fe,Ni)OOH is found to be the electrocatalytic active phase. Furthermore, we integrate the sulfurated stainless steel electrode into an industrial alkaline electrolyzer as the anode (400 cm2). Our results demonstrate that the electrolyzer based on the sulfurated stainless steel electrode exhibits a better catalytic activity than the electrolyzer based on the Raney nickel electrode, a widely-adopted electrode in commercial water–alkali electrolyzers, and delivers a catalytic current of c.a. 300 mA cm–2 for over 120 h under the industrial catalytic conditions (30% KOH, 80 °C). [Display omitted] • A square meter-sized, sulfurated stainless steel meshes is prepared under ambient conditions. • The sulfurated stainless steel displays great OER activity and impressive stability for over 1000 h. • The in situ formed, γ -(Fe,Ni)OOH on stainless steel surfaces are identified as a highly active catalytic phase. • The sulfurated stainless steel is integrated into an industrial electrolyzer (400 cm2) as highly active and stable anode. [ABSTRACT FROM AUTHOR]

Nanoporous sulfur-doped graphitic carbon nitride microrods are prepared by direct thermal condensation of a high-quality melamine-trithiocyanuric acid supramolecular cocrystal under N 2 atmosphere. The as-obtained carbon nitride material serves as a highly active photocatalyst for H 2 evolution under visible-light irradiation, affording an activity about 9.3 times higher than that of the reference carbon nitride material that is prepared using melamine as the precursor. In addition, this material also exhibits satisfactory stability because there is no loss of catalytic activity after the catalytic H 2 evolution for 60 h. The simultaneous achievement of the porosity, sulfur-doping and 1D morphology in the carbon nitride material as well as its superior photocatalytic activity, in turn, highlights the importance of the synthetic strategy reported herein. [ABSTRACT FROM AUTHOR]

The importance of interstitial boron ordering in Pd-B alloy catalysts for attaining a desirable microstructural requirement and bringing about optimal near-surface electronic structure for HER has been demonstrated, with both theoretical and experimental studies. Intermetallic Pd 2 B has been demosntrated to be such a material that exhibits Pt-like activity for HER. [Display omitted] • Interstitial B ordering was confirmed to optimize near-surface electronic structure of Pd. • Highly-crystalline and high purity intermetallic Pd 2 B was synthesized. • The Pd 2 B exhibited Pt-like catalytic activity and excellent stability for HER. The fundamental understanding and precise tuning of interatomic s,p-d orbital hybridization are critical to the design of interstitial alloy catalysts containing light constituent atoms. Here, we present a joint theoretical and experimental study that reveals the importance of distribution, concentration and ordering of interstitial boron atoms in Pd-B alloy's near-surface electronic structure and catalytic performance. Our theoretical results demonstrate that the sub-surface location of interstitial boron atoms with a Pd:B atomic ratio of 2:1 is necessary to ensure an appropriate degree of interatomic s,p-d orbital hybridization, and thereby an optimal surface electronic structure for the hydrogen evolution reaction (HER). We experimentally achieve this with highly-crystalline intermetallic Pd 2 B. Due to its optimal electronic structure and ordered arrangement of interstitial boron atoms, the intermetallic Pd 2 B exhibits Pt-like catalytic activity for HER and has excellent catalytic stability for over seven days. [ABSTRACT FROM AUTHOR]