The plating/stripping of Li dendrites can fracture the static solid electrolyte interphase (SEI) and cause significant dynamic volume variations in the Li anode, which give rise to poor cyclability ...and severe safety hazards. Herein, a tough polymer with a slide‐ring structure was designed as a self‐adaptive interfacial layer for Li anodes. The slide‐ring polymer with a dynamically crosslinked network moves freely while maintaining its toughness and fracture resistance, which allows it can to dissipate the tension induced by Li dendrites on the interphase layer. Moreover, the slide‐ring polymer is highly stretchable, elastic, and displays an ultrafast self‐healing ability, which allows even pulverized Li to remain coalesced without disintegrating upon consecutive cycling. The Li anodes demonstrate greatly improved suppression of Li dendrite formation, as evidenced by the high critical current density (6 mA cm−2) and stable cycling for the full cells with high‐areal capacity LiFePO4, high‐voltage NCM, and S cathodes.
A slide‐ring polymer with a high stiffness, high toughness and excellent fracture resistance is designed to adapt its shape to dynamic electrode volume variations and stabilize the lithium anode upon cycling.
Neutral electrolysis to produce hydrogen is prime challenging owing to the sluggish kinetics of water dissociation for the electrochemical reduction of water to molecular hydrogen. An ion‐enriched ...electrode/electrolyte interface for electrocatalytic reactions can efficiently obtain a stable electrolysis system. Herein, we found that interfacial accumulated fluoride ions and the anchored Pt single atoms/nanoparticles in catalysts can improve hydrogen evolution reaction (HER) activity of NiFe‐based hydroxide catalysts, prolonging the operating stability at high current density in neutral conditions. NiFe hydroxide electrode obtains an outstanding performance of 1000 mA cm−2 at low overpotential of 218 mV with 1000 h operation at 100 mA cm−2. Electrochemical experiments and theoretical calculations have demonstrated that the interfacial fluoride contributes to promote the adsorption of Pt to proton for sustaining a large current density at low potential, while the Pt single atoms/nanoparticles provide H adsorption sites. The synergy effect of F and Pt species promotes the formation of Pt─H and F─H bonds, which accelerate the adsorption and dissociation process of H2O and promote the HER reaction with a long‐term durability in neutral conditions.
The interfacial accumulated fluoride ions and the anchored Pt single atoms/nanoparticles improve hydrogen evolution reaction activity and stability of NiFe‐based hydroxide catalysts in neutral conditions.
Operating fuel cells in alkaline environments permits the use of platinum-group-metal-free (PGM-free) catalysts and inexpensive bipolar plates, leading to significant cost reduction. Of the PGM-free ...catalysts explored, however, only a few nickel-based materials are active for catalyzing the hydrogen oxidation reaction (HOR) in alkali; moreover, these catalysts deactivate rapidly at high anode potentials owing to nickel hydroxide formation. Here we describe that a nickel-tungsten-copper (Ni
WCu
) ternary alloy showing HOR activity rivals Pt/C benchmark in alkaline electrolyte. Importantly, we achieved a high anode potential up to 0.3 V versus reversible hydrogen electrode on this catalyst with good operational stability over 20 h. The catalyst also displays excellent CO-tolerant ability that Pt/C catalyst lacks. Experimental and theoretical studies uncover that nickel, tungsten, and copper play in synergy to create a favorable alloying surface for optimized hydrogen and hydroxyl bindings, as well as for the improved oxidation resistance, which result in the HOR enhancement.
Porous materials, especially metal–organic frameworks, covalent organic frameworks, and supramolecular organic frameworks, are widely used in heterogeneous catalysis, adsorption, and ion exchange. ...Cucurbitnurils (Qns) suitable building units for porous materials because they possess cavities with neutral electrostatic potential, portal carbonyls with negative electrostatic potential, and outer surfaces with positive electrostatic potential, which may result in the formation of Qn‐based supramolecular frameworks (QSFs) assembled through the interaction of guests within Qns, the coordination of Qns with metal ions, and outer‐surface interaction of Qns (OSIQ). This review summarizes the various QSFs assembled via OSIQs. The QSFs can be classified as being assembled by 1) self‐induced OSIQ, 2) anion‐induced OSIQ, and 3) aromatic‐induced OSIQ. The design and construction of QSFs with novel structures and specific functional properties may establish a new research direction in Qn chemistry.
This review summarizes the outer‐surface interactions of cucurbitnurils (OSIQ) in various simple cucurbitnuril‐based supramolecular frameworks (QSFs) and QSFs assembled via self‐induced OSIQ, anion‐induced OSIQs, and aromatic‐induced OSIQs. The design and construction of QSFs with novel structures and specific functional properties establishes a new research direction in cucurbitnuril chemistry.
The chloride ions in seawater result in corrosion, low catalytic efficiency, and poor stability of the electrocatalysts in direct seawater electrolysis, which limits the use of large‐scale seawater ...electrolysis technology. Herein, a corrosion‐resistant Ag/NiFeRu layered double hydroxide (LDH) electrocatalyst for seawater electrolysis at industrial current density, in which Ru and Ag species in the catalyst can have a corrosion‐resistance of chloride ions from the anode surface and enhance its robustness in seawater is designed. The catalyst requires the overpotentials of 256 and 287 mV to obtain a current density of 1 A cm−2 in 1 m KOH and 1 m KOH + seawater, respectively. More importantly, it works stably for over 1000 h at 1 A cm−2 in alkaline seawater. Further quasi‐industrial conditions measurement (6 m KOH + seawater, 60 °C) shows a markedly low overpotential of 174 mV at 1 A cm−2 on Ag/NiFeRu LDH, obtaining over 140 h under harsh industrial conditions. Theoretical calculations demonstrate that the Ru species can effectively regulate the local electronic structure of NiFe LDH, and enhance the intrinsic activity of NiFe LDH. The transformation of Ag2O from Ag during OER stabilizes the Fe site in NiFe LDH, which improves the overall stability of the electrocatalyst.
Ru and Ag synergetic regulation NiFe LDH exhibits excellent activity and stability in industrial seawater electrolysis. This catalyst requires a low overpotential of 287 mV to obtain a current density of 1 A cm−2 in 1 m KOH + seawater with a long‐term operation of 1000 h.
Layered molybdenum disulfide has demonstrated great promise as a low-cost alternative to platinum-based catalysts for electrochemical hydrogen production from water. Research effort on this material ...has focused mainly on synthesizing highly nanostructured molybdenum disulfide that allows the exposure of a large fraction of active edge sites. Here we report a promising microwave-assisted strategy for the synthesis of narrow molybdenum disulfide nanosheets with edge-terminated structure and a significantly expanded interlayer spacing, which exhibit striking kinetic metrics with onset potential of -103 mV, Tafel slope of 49 mV per decade and exchange current density of 9.62 × 10(-3) mA cm(-2), performing among the best of current molybdenum disulfide catalysts. Besides benefits from the edge-terminated structure, the expanded interlayer distance with modified electronic structure is also responsible for the observed catalytic improvement, which suggests a potential way to design newly advanced molybdenum disulfide catalysts through modulating the interlayer distance.
Ammonia (NH3) is recognized as a transportable carrier for renewable energy fuels. Photoelectrochemical nitrate reduction reaction (PEC NO3RR) offers a sustainable solution for nitrate‐rich ...wastewater treatment by directly converting solar energy to ammonia. In this study, we demonstrate the highly selective PEC ammonia production from NO3RR by constructing a CoCu/TiO2/Sb2Se3 photocathode. The constructed CoCu/TiO2/Sb2Se3 photocathode achieves an ammonia Faraday efficiency (FE) of 88.01 % at −0.2 VRHE and an ammonia yield as high as 15.91 μmol h−1 cm−2 at −0.3 VRHE with an excellent onset potential of 0.43 VRHE. Dynamics experiments and theoretical calculations have demonstrated that the CoCu/TiO2/Sb2Se3 photocathode possesses high light absorption capacity, excellent carrier transfer capability, and high charge separation and transfer efficiencies. The photocathode can effectively adsorb the reactant NO3− and intermediate, and the CoCu co‐catalyst increases the maximum Gibbs free energy difference between NO3RR and HER. Meanwhile, the Co species enhances the spin density of Cu, and increases the density of states near the Fermi level in pdos, which results in a high PEC NO3RR activity on CoCu/TiO2/Sb2Se3. This work provides a new avenue for the feasibility of efficient PEC ammonia synthesis from nitrate‐rich wastewater.
The highly selective photoelectrochemical ammonia production from NO3 reduction reaction can be achieved by constructing a CoCu/TiO2/Sb2Se3 photocathode. The photocathode achieves an ammonia Faraday efficiency of 88.01 % and an ammonia yield as high as 15.91 μmol h−1 cm−2 with an excellent onset potential of 0.43 VRHE. It provides a new avenue for the feasibility of efficient PEC ammonia synthesis from nitrate‐rich wastewater.
The anode oxygen evolution reaction (OER) is known to largely limit the efficiency of electrolyzers owing to its sluggish kinetics. While crystalline metal oxides are promising as OER catalysts, ...their amorphous phases also show high activities. Efforts to produce amorphous metal oxides have progressed slowly, and how an amorphous structure benefits the catalytic performances remains elusive. Now the first scalable synthesis of amorphous NiFeMo oxide (up to 515 g in one batch) is presented with homogeneous elemental distribution via a facile supersaturated co‐precipitation method. In contrast to its crystalline counterpart, amorphous NiFeMo oxide undergoes a faster surface self‐reconstruction process during OER, forming a metal oxy(hydroxide) active layer with rich oxygen vacancies, leading to superior OER activity (280 mV overpotential at 10 mA cm−2 in 0.1 m KOH). This opens up the potential of fast, facile, and scale‐up production of amorphous metal oxides for high‐performance OER catalysts.
Amorphous NiFeMo oxide (up to 515 g one batch) with homogeneous elemental distribution was synthesized through a facile supersaturated co‐precipitation method. The amorphous NiFeMo oxide undergoes rapid surface self‐reconstruction during OER that forms a metal oxy(hydroxide) active layer with oxygen vacancies, enabling efficient OER catalysis.
Platinum on carbon (Pt/C) catalyst is commercially adopted in fuel cells but it undergoes formidable active‐site poisoning by carbon monoxide (CO). In particular, given the sluggish kinetics of ...hydrogen oxidation reaction (HOR) in anion‐exchange membrane fuel cell (AEMFC), the issues of Pt poisoning and slow rate would combine mutually, notably worsening the device performances. Here we overcome these challenges through incorporating cobalt (Co) into molybdenum‐nickel alloy (MoNi4), termed Co‐MoNi4, which not only shows superior HOR activity over the Pt/C catalyst in alkali, but more intriguingly exhibits excellent CO tolerance with only small activity decay after 10 000 cycles in the presence of 500 parts per million (ppm) CO. When feeding with CO (250 ppm)/H2, the AEMFC assembled by this catalyst yields a peak power density of 394 mW cm−2, far exceeding the Pt/C catalyst. Experimental and computational studies reveal that weakened CO chemisorption originates from the electron‐deficient Ni sites after Co incorporation that suppresses d→CO 2π* back‐donation.
Incorporating Co into MoNi4 nanocatalyst can suppress the d→CO 2π* back donation, leading to excellent CO tolerance. When feeding with CO (250 ppm)/H2, the fuel cell assembled by this catalyst yields a peak power density of 394 mW cm−2, exceeding that of 209 mW cm−2 for the Pt/C catalyst.
PDF
