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Single-atom catalysts (SACs) with high catalytic activity as well as great stability are demonstrating great promotion in electrocatalytic energy conversion, which is also a big challenge to achieve. Herein, we proposed a facile synthetic strategy to construct nickel-iron bimetallic hydroxide nanoribbon stabilized single-atom iridium catalysts (Ir-NiFe-OH), where the nickel-iron hydroxide nanoribbon not only can serve as good electronic conductor, but also can well stabilize and fully expose single-atom sites. Adopted as catalyst for urea oxidation reaction (UOR), it exhibited excellent UOR performance that it only needed a low operated potential of 1.38 V to achieve the current density of 100 mA·cm−2. In-situ Fourier transform infrared spectroscopy, X-ray absorption spectrum, and density functional theory calculations proved that Ir species are active centers and the existence of both Ni and Fe in the local structure of Ir atom can optimize the d-band center of Ir species, promoting the adsorption of intermediates and desorption of products for UOR. The hydrogen evolution reaction (HER)/UOR electrocatalytic cell demanded voltages of 1.46 and 1.50 V to achieve 50 and 100 mA·cm−2, respectively, which demonstrated a higher activity and better stability than those of conventional catalysts. This work opens a new avenue to develop catalysts for UORs with boosted activity and stability. [ABSTRACT FROM AUTHOR]

Electrocatalytic CO2 reduction (CO2ER) to valuable chemicals, for example, HCOOH have received widespread attention, which still suffers from moderate Faradaic efficiency with low current regarding the wide industrial application of HCOOH. Herein, we employed a strategy of modifying electronic metal‐support interaction (EMSI) by fabricating Bi nanoparticles supported Ni‐modified Bi2O2CO3 (Bi/Ni‐BOC) heterostructure. The obtained Bi/Ni‐BOC exhibited high formate Faradic efficiency (FEHCOOH) of 97% at −2.1 V (vs. Ag/AgCl) and above 90% within broad potential range (−1.7 to −2.2 V) in flow cell with superior stability at high current density of ~220 mA cm−2, and formate concentration can reach 2.4 mmol h−1 cm−2 at −2.3 V. In/ex situ x‐ray absorption fine structure (XAFS) and density functional theory (DFT) calculation indicated that Ni doping promoted the enhancement of EMSI, which improved the generation and stable existence of electron‐rich Bi to boost CO2 activation and *OHCO hydrogenation, thus facilitating highly‐efficient formate production with hydrogen evolution reaction (HER) inhibition. [ABSTRACT FROM AUTHOR]

Understanding the correlation between the structural evolution of electrocatalysts and their catalytic activity is both essential and challenging. In this study, we investigate this correlation in the context of the oxygen evolution reaction (OER) by examining the influence of structural disorder during and after dynamic structural evolution on the OER activity of Fe−Ni (oxy)hydroxide catalysts using operando X‐ray absorption spectroscopy, alongside other experiments and theoretical calculations. The Debye–Waller factors obtained from extended X‐ray absorption fine structure analyses reflect the degree of structural disorder and exhibit a robust correlation with the intrinsic OER activities of the electrocatalysts. The enhanced OER activity of in situ‐generated metal (oxy)hydroxides derived from different pre‐catalysts is linked to increased structural disorder, offering a promising approach for designing efficient OER electrocatalysts. This strategy may inspire similar investigations in related electrocatalytic energy‐conversion systems. [ABSTRACT FROM AUTHOR]

Pt cocatalyst play bifunctions in the photoreforming of polyethylene terephthalate plastic waste by improving the charge transfer kinetics and regulating the adsorption-desorption of oxidation intermediates, thereby achieving efficient photocatalytic H 2 evolution rate and producing valuable commodities in the photoreforming reactions. [Display omitted] Upcycle polyethylene terephthalate (PET) waste by photoreforming (PR) is a sustainable and green approach to tackle environmental problems but with challenges to obtain valuable oxidation products and high purity hydrogen simultaneously. Noble metal cocatalysts are essential to enhance the overall PR reaction efficacy. In this work, TiO 2 nanotubes (TiO 2 NTs) decorated with single Pt atoms (Pt 1 /TiO 2) or Pt nanoparticles (Pt NPs /TiO 2) are used in the photoreforming reaction (in one batch), and the oxidation products from ethylene glycol (EG, hydrolysed product of PET) in liquid phase and hydrogen are detected. With Pt 1 /TiO 2 , EG is oxidized to glyoxal, glyoxylate or lactate, and hydrogen evolution rate (r H 2) reaches 51.8 μmol⋅h−1⋅g cat −1, that is 30 times higher than that of TiO 2. For Pt NPs /TiO 2 (size of Pt NPs: 1.97 nm), hydrogen evolution reaches 219.1 μmol⋅h−1⋅g cat −1, but with the oxidation product of acetate only. DFT calculation demonstrates that for Pt NPs, the reaction path for hydrogen evolution is preferred thermodynamically, due to the formation of Schottky junction. On the oxidation of EG, theoretical and spectroscopic analysis suggest that bidentate adsorption of EG at the interface is facile on Pt 1 /TiO 2 , compared to that on Pt NPs /TiO 2 (two Pt sites), but oxidation products, adsorb less strongly, compared to Pt NPs /TiO 2 , that eventually regulates the distribution of oxidation products. The results thus demonstrate the bifunctions of Pt in the PR reaction, i.e., electron transfer mediator for hydrogen evolution and reactive sites for molecules adsorption. The oxidation reaction is dominated by the adsorption-desorption behavior of molecules but the reduction reaction is controlled by the electron transfer. In addition, acidification of pretreated PET alkaline solution achieves separation of pure terephthalic acid (PTA), which further improves the reaction efficiency possibly by offering high density of active sites and acidic environment. Our work thus demonstrates that to upcycle PET plastics, an optimized process can be reached by atomic design of photocatalysts and proper treatment on the plastic wastes. [ABSTRACT FROM AUTHOR]

Urea is of great importance for the survival and development of mankind because of its advantages in effectively increasing crop yields. A novel carbon-supported indium-doped bismuth nanoparticles (Bi: 10 %In/C NPs) was prepared for the synthesis of urea via the co-activated reduction of nitrate and CO 2 with an average Faraday efficiency (FE) of 20.31 % and urea yield (R urea) of 606.38 μg mg−1 h−1. Interestingly, the In doped here not only serves as the active site, but also acts as an activator to stimulate the activity of Bi through electronic interaction, thus making Bi also the active site for the electrocatalytic C-N coupling reaction. Simultaneously, the key intermediates of the reaction are revealed to be *NH 2 and *CO. This work provides further insight into the role of indium in the electrocatalytic C-N coupling for the synthesis of urea, which gives a direction for thinking about the design and construction of subsequent highly efficient electrocatalysts. A novel catalyst based on carbon-supported In-doped Bi nanoparticles (Bi:10 % In/C NPs) was prepared for the co-activated reduction of nitrate and CO 2 for the synthesis of urea with average FE and urea yield of 20.31 % and 606.38 μg mg−1 h−1 at − 0.45 V vs. RHE. The key intermediates of the reaction are revealed to be *NH 2 and *CO. Interestingly, experimental results show that the doped In acts not only as the active site but also as an "activator", stimulating the activity of Bi through electronic interactions, thus making Bi also the active site for electrocatalytic C-N coupling reactions. [Display omitted] ● A bismuth-based catalyst well suited for the electrochemical synthesis of urea (FE: 20.31 %, R urea : 606.38 μg mg−1 h−1) was prepared by a simple room temperature reduction method based on the property of bismuth to inhibit competitive hydrogen evolution reactions. ● A strategy for the preparation of electrocatalysts for highly efficient urea synthesis using direct activation of bismuth by indium is proposed for the first time. ● Theindium in the prepared Bi:In/C not only directly participates in the synthesis of urea as the active site, but also acts as an activator to activate the inert bismuth, so that bismuth also becomes the active site of the C-N coupling reaction, thus greatly improving the efficiency and stability for the synthesis of urea. [ABSTRACT FROM AUTHOR]