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Bubble evolution in electrolysis commonly initiates from nanobubbles (NBs), and their ultrasmall size induces unique high internal pressure and consequently high anti-potential, namely, the extra overpotential, which is of great significance but still remains rather vague. Herein, we employ the in situ electrochemical surface plasmon resonance imaging method as combined with atomic force microscopy measurement to track the formation and growth of interfacial NBs during initiative hydrogen evolution reaction. We find that NBs’ growth initiate from pancake shaped ones with increasing coverage and roughly pinned three-phase boundaries and increasing contact angle and height, but the coverage remains almost unchanged after reaching equilibrium state; Further increasing overpotential leads to the rise of NBs’ curvature (anti-potential), as well as higher gas outflux rate, namely, higher background current. As confirmed by molecular dynamics simulation, the “pin-rise” growth mode and the quantitative influence of NBs on the electrochemical performance has been revealed.

Photoelectrochemical cells are emerging as powerful tools for organic synthesis. However, they have rarely been explored for C–H halogenation to produce organic halides of industrial and medicinal importance. Here we report a photoelectrocatalytic strategy for C–H halogenation using an oxygen-vacancy-rich TiO2 photoanode with NaX (X=Cl−, Br−, I−). Under illumination, the photogenerated holes in TiO2 oxidize the halide ions to corresponding radicals or X2, which then react with the substrates to yield organic halides. The PEC C–H halogenation strategy exhibits broad substrate scope, including arenes, heteroarenes, nonpolar cycloalkanes, and aliphatic hydrocarbons. Experimental and theoretical data reveal that the oxygen vacancy on TiO2 facilitates the photo-induced carriers separation efficiency and more importantly, promotes halide ions adsorption with intermediary strength and hence increases the activity. Moreover, we designed a self-powered PEC system and directly utilised seawater as both the electrolyte and chloride ions source, attaining chlorocyclohexane productivity of 412 µmol h−1 coupled with H2 productivity of 9.2 mL h−1, thus achieving a promising way to use solar for upcycling halogen in ocean resource into valuable organic halides., Photoelectrochemical cells are promising tools for C–H functionalisation coupled with H2 production. In this work, Duan et. al., reported the photoelectrocatalytic C–H halogenation to produce organic halides of industrial and medicinal importance with promoted H2 production.

Replacing the sluggish oxygen evolution reaction (OER) with oxidation reactions for the synthesis of complex pharmaceutical molecules coupled with enhanced hydrogen evolution reaction (HER) is highly attractive, but it is rarely explored. Here, we report an electrochemical protocol for selective oxidation of sulfides to sulfoxides over a CoFe layered double hydroxide (CoFe-LDH) anode in an aqueous-MeCN electrolyte, coupled with 2-fold promoted cathodic H2 productivity. This protocol displays high activity (85–96% yields), catalyst stability (10 cycles), and generality (12 examples) in selective sulfide oxidation. We demonstrate its applicability in the synthesis of four important pharmaceutical related sulfoxide compounds with scalability (up to 1.79 g). X-ray spectroscopy investigations reveal that the CoFe-LDH material evolved into amorphous CoFe-oxyhydroxide under catalytic conditions. This work may pave the way towards sustainable organic synthesis of valuable pharmaceuticals coupled with H2 production., Replacing anodic OER with selective sulfide oxidation produces sulfoxide-related pharmaceutical compounds over a CoFe-LDH catalyst with enhanced HER, providing a sustainable protocol for valuable pharmaceuticals synthesis without external oxidants.

Electrochemical alcohols oxidation offers a promising approach to produce industrial-relevant chemicals and facilitate coupled H 2 production. However, the corresponding current density is very low at moderate cell potential that substantially limits the overall productivity. Here, we report enrichment of alcohols in local environment over a cooperative catalyst of Au nanoparticles supported on cobalt oxyhydroxide nanosheets (Au/CoOOH), enabling alcohols electrooxidation at high current density. Specifically, the current density of benzyl alcohol electrooxidation can reach 523 mA cm− 2 at potential of 1.5 V vs. RHE. Experimental and theoretical results suggest that benzyl alcohol molecules are enriched on Au/CoOOH interface via strong d-π interaction. The enrichment has a broad substrate scope that involves alcohols with α-π bond including α-phenyl, C = C and C = O groups. Based on these findings, we design an intermittent potential (IP) strategy for long-term alcohol enrichment, achieving electrooxidation with current density of > 250 mA cm− 2 over 24 hours and promoted productivity.

Summary Electroreduction of CO2 into value-added products is an effective approach to remit the environmental and energy issues. However, the development of an effective, accessible, and simple method for mass production of electrocatalyst is challenging. Herein, we demonstrate the solid-state diffusion between the N-doped carbon phase and bulk Ni metal can be utilized to synthesize hierarchical, self-supported, and atomistic catalyst. Strikingly, this hierarchical catalyst is programmable and scalable to meet the industrial demand and can be directly used as a binder-free electrode toward the CO2 electroreduction, delivering a state-of-the-art current density of 48.66 mA cm−2 at −1.0 V versus reversible hydrogen electrode (RHE) and high faradic efficiency of 97% to CO. The selectivity can be retained over 90% in a wide range of working potential of −0.7 to −1.2 V versus RHE. This solid-state diffusion strategy presents great potential to produce hierarchical and atomistic catalysts at industrial levels.

Single Ru atoms are uniquely located on the top of trivalence Fe atom of NiFe layered double hydroxide., The catalytic properties of single-atom catalysts (SACs) can be influenced largely by the chemical environment exerted by supports. Therefore, a precise location of the single atom is essential for understanding of the reaction mechanism and design of novel SACs. However, the preparation of SACs with a precise location remains a great challenge. Herein, we report a facile one-step method to synthesize single Ru atoms supported on a monolayer NiFe-layered double hydroxide (mono-NiFe). Detailed studies demonstrate that the single Ru atoms are not dispersed randomly in the LDH structure, but are uniquely located on the top of the Fe-metal atom of mono-NiFe via three oxygen atoms. Furthermore, these SACs prove to be highly active for the hydrazine electrooxidation reaction. Density functional theory calculations demonstrate that the single Ru atoms can stabilize the hydrazine electrooxidation intermediate with one unpaired electron (*N2H3 and *N2H), thus lowering the reaction barrier for the rate-determining step. Moreover, the loading amount of single Ru atoms with a precise location can even go up to 7.0 wt% without any aggregation.

Oxygen reduction efficiency holds the key for renewable energy technologies including fuel cells and metal-air batteries, which involves coupling diffusion-reaction-conduction processes at the interface of catalyst/electrolyte, and thus rational electrode design facilitating mass transportation stands as a key issue for fast oxygen reduction reaction (ORR). Herein, we report a Janus electrode with asymmetric wettability prepared by partly modifying aerophobic nitrogen doped carbon nanotube arrays with polytetrafluoroethylene (PTFE) as a high performance catalytic electrode for ORR. The Janus electrode with opposite wettability on adjacent sides maintains stable gas reservoir in the aerophilic side while shortening O2 pathway to catalysts in the aerophobic side, resulting in superior ORR performance (22.5 mA/cm2 @ 0.5 V) than merely aerophilic or aerophilic electrodes. The Janus electrode endows catalytic performance even comparable to commercial Pt/C in the alkaline electrolyte, exploiting a previously unrecognized opportunity that guides electrode design for the gas-consumption electrocatalysis.

Summary New types of cation storage materials would show tremendous potential in the development of high-performance rechargeable energy storage devices. Herein, we develop layered double hydroxides (LDHs) as promising cation supercapacitor materials in aqueous and neutral operation, via an effective electrochemical activation strategy, for a reversible intercalation of a wide range of metal cations. These activated LDH materials exhibit overwhelming metal-ion storage capacities in aqueous electrolytes as a result of the phase transformation of LDH (repulsive to cations) to hydrogen-vacancy-enriched LDH (LDH-HV, attractive to cations) induced by the electrochemical activation process. The activated LDH-HV phase provides a two-dimensional open channel with abundant active sites (HV) for a reversible intercalation of metal ions, accounting for the significantly enhanced energy storage performance. This vacancy-induced cation intercalation into LDHs builds up a general approach for developing earth-abundant transition-metal resources as a prospective energy storage material toward a large variety of cation supercapacitors.

When the dimensionality of layered compounds decreases to the physical limit, ultimate two-dimensional (2D) anisotropy and/or quantum confinement effects may lead to extraordinary physicochemical attributes. Here, we report single-layer Rh nanosheets (NSs) exhibiting ultrahigh peroxidase-like activity, far exceeding that of horseradish peroxidase (HRP) and of most known layered nanomaterial-based peroxidase mimics. Considering per NS as an active subunit, the Rh NSs displayed a catalytic rate constant (Kcat) as high as 4.45 × 105 s–1 to H2O2, two orders of magnitude higher than those of HRP and Rh nanoparticles. The high atom efficiency of the Rh NSs can be attributed to the full exposure of surface-active Rh atoms, which greatly facilitates electron transfer and formation of superoxide anions, representing reactive oxygen species in the catalytic process. As a proof-of-concept application, the Rh NSs were successfully used as peroxidase mimics for the colorimetric detection of H2O2 and xanthine, with high sensitivity and selectivity. Moreover, a simple, rapid, and sensitive Rh-based paper sensor for ascorbic acid was also developed. In summary, this work provides a novel example of single-layer metallic NSs for biosensing.

The search for active, stable, and cost-efficient electrocatalysts for hydrogen production via water splitting could make a substantial impact on energy technologies that do not rely on fossil fuels. Here we report the synthesis of rhodium phosphide electrocatalyst with low metal loading in the form of nanocubes (NCs) dispersed in high-surface-area carbon (Rh2P/C) by a facile solvo-thermal approach. The Rh2P/C NCs exhibit remarkable performance for hydrogen evolution reaction and oxygen evolution reaction compared to Rh/C and Pt/C catalysts. The atomic structure of the Rh2P NCs was directly observed by annular dark-field scanning transmission electron microscopy, which revealed a phosphorus-rich outermost atomic layer. Combined experimental and computational studies suggest that surface phosphorus plays a crucial role in determining the robust catalyst properties.

Although molecular dinitrogen (N2) is widely used as a carrier or inert gas for many catalytic reactions, it is rarely considered as a catalytic promoter. Here, we report that N2 could be used to reduce the activation energy for catalytic hydrodeoxygenation over ruthenium-based catalysts. Specifically, we report a 4.3-fold activity increase in the catalytic hydrodeoxygenation of p-cresol to toluene over a titanium oxide supported ruthenium catalyst (Ru/TiO2) by simply introducing 6 bar N2 under batch conditions at 160 °C and 1 bar hydrogen. Detailed investigations indicate that N2 can be adsorbed and activated on the metallic ruthenium surface to form hydrogenated nitrogen species, which offer protic hydrogen to lower the activation energy of direct carbonaromatic–oxygen bond scission and the hydrogenation of hydroxy groups. Thus, by employing different ruthenium catalysts, including Ru/TiO2, Ru/Al2O3, Ru/ZrO2 and Ru/C, we demonstrate that N2 promotion of hydrodeoxygenation can be regarded as a general strategy. Due to its stability nitrogen is often employed as an inert gas during catalytic reactions. Now, a study shows that N2 can act as promoter for the catalytic hydrodeoxygenation of p-cresol on supported ruthenium catalysts through the formation of hydrogenated nitrogen species acting as a source of protic hydrogen.

Cadmium (Cd) contaminated cropland has posed severe risks to human health. While in-situ Cd immobilization by stabilizer has been widely adopted in practice, there is still a huge challenge to develop cost-effective stabilizers with strong and long-term immobilization ability. In this work, we report a CaAl-layered double hydroxide (CaAl-LDH) as an efficient stabilizer for Cd2+ in-situ immobilization both in lab scale and practice remediation. This material presents fast sorption rate (ca. 5 min) and high capture capacity (592 mg/g) towards Cd2+ in solution, and high immobilization efficiency (up to 96.9%) in soil remediation. Detailed investigations suggest that Cd2+ induces the reconstructing of CaAl-LDH to CdAl-LDH, with Cd being stabilized in a super stable state. In a large-scale and long-term application (in soil of 10 ha for continuous three years’ test), we observe that the CaAl-LDH enables a low Cd content in wheat grain (0.06 mg/kg) that is below the national standard (0.1 mg/kg). By employing a scaling-up production in 3000 ton per year, we demonstrate the CaAl-LDH would be a promising competitive candidate for facile and cost-efficient remediation of Cd contaminated soil.

Two-dimensional nanomaterials (2DNMs) have attracted increasing attention due to their unique properties and promising applications. Unlike 2DNMs with lamellar structures, metal ultrathin 2DNMs are difficult to synthesize and stabilize because they tend to form close-packed crystal structures. Most reported cases consist of monometallic and heterogeneous nanostructures. The synthesis of metal alloy 2DNMs has been rarely reported. Here, we report the synthesis of PdNi alloy wavy nanosheets (WNSs) using an enhanced CO-confinement strategy. This strategy is also suitable to the synthesis of other Pd-based alloy WNSs such as PdCu, PdFe, and even a trimetallic PdFeNi.

A facile method for the synthesis of a series of mesoporous silica nanoporous (MSN) aqueous miscible organic layered double hydroxide core@shell nanocomposites using MCM-41, Al-MCM-41, SBA-15, and MCM-48 as the core is reported. These materials exhibit hierarchical morphologies with high surface areas and good porosity. Chemically, these materials offer controllable bifunctional basicity and acidity.

The fabrication of cost effective and efficient electrocatalysts with functional building blocks to replace noble metal ones is of great importance for energy related applications yet remains a great challenge. Herein, we report the fabrication of a hierarchical structure containing CNTs/graphene/transition-metal hybrids (h-NCNTs/Gr/TM) with excellent bifunctional oxygen electrocatalytic activity. The synthesis was rationally designed by the growth of shorter nitrogen-doped CNTs (S-NCNTs) on longer NCNTs arrays (L-NCNTs), while graphene layers were in situ generated at their interconnecting sites. The hybrid material shows excellent OER and ORR performance, and was also demonstrated to be a highly active bifunctional catalyst for Zn–air batteries, which could be due to rapid electron transport and full exposure of active sites in the hierarchical structure.

Despite significant advances in the fabrication and applications of graphene-like materials, it remains a challenge to prepare single-layered metallic materials, which have great potential applications in physics, chemistry and material science. Here we report the fabrication of poly(vinylpyrrolidone)-supported single-layered rhodium nanosheets using a facile solvothermal method. Atomic force microscope shows that the thickness of a rhodium nanosheet is

The nanoscience and nanotechniques have brought with new chance for new applications of some traditional materials, for instance, ceria-based materials, which are of great interest due to their wide applications, in particular, as redox or oxygen storage promoters in the three-way catalysts, catalysts for H(2) production from fuels, and solid state conductors for fuel cells. We highlight here current research activities focused on the controlled synthesis and assembly of ceria-based nanomaterials. We begin with a brief introduction to the urgency for research of ceria-based nanomaterials and our different consideration. Typical synthesis is then discussed with examples of nanosized ceria, ceria-zirconia solid solutions, and doped ceria developed by our group and the others. Controlled synthesis to manipulate the shape, crystal plane, and size is the topic of this article, with approaches elaborated for the assembly of ceria-based materials. Finally, we conclude this article with personal understandings and perspectives on this exciting realm.