Interface and M^(3+)/M^(2+)Valence Dual-Engineering on Nickel Cobalt Sulfoselenide/Black Phosphorus Heterostructure for Efficient Water Splitting Electrocatalysis

The catalyst innovation that aims at noble-metal-free substitutes is one key aspect for future sustainable hydrogen energy deployment.In this paper,a nickel cobalt sulfoselenide/black phosphorus heterostructure(NiCoSe|S/BP)was fabricated to realize the highly active and durable water electrolysis through interface and valence dual-engineering.The NiCoSe|S/BP nanostructure was constructed by in-situ growing NiCo hydroxide nanosheet arrays on few-layer BP and subsequently one-step sulfoselenization by SeS2.Besides the conductive merit of BP substrate,holes in p-type BP are capable of oxidizing the Co^(2+)to high-valence and electron-accepting Co^(3+),benefiting the oxygen evolution reaction(OER).Meanwhile,Ni^(3+)/Ni^(2+)ratio in the heterostructure is reduced to maintain the electrical neutrality,which corresponds to the increased electron-donating character for boosting hydrogen evolution reaction(HER).As for HER and OER,the heterostructured NiCoSe|S/BP electrocatalyst exhibits small overpotentials of 172 and 285 mV at 10 mA cm^(-2)(η_(10))in alkaline media,respectively.And overall water splitting has been achieved at a low cell potential of 1.67 V at η_(10) with high stability.Molecular sensing and density functional theory(DFT)calculations are further proposed for understanding the rate-determine steps and enhanced catalytic mechanism.The investigation presents a deep-seated perception for the electrocatalytic performance enhancement of BP-based heterostructure.

Shining Light on Anion-Mixed Nanocatalysts for Efficient Water Electrolysis: Fundamentals, Progress, and Perspectives

Hydrogen with high energy density and zero carbon emission is widely acknowledged as the most promising candidate toward world’s carbon neutrality and future sustainable eco-society.Water-splitting is a constructive technology for unpolluted and high-purity H2 production,and a series of non-precious electrocatalysts have been developed over the past decade.To further improve the catalytic activities,metal doping is always adopted to modulate the 3d-electronic configuration and electron-donating/accepting(e-DA)properties,while for anion doping,the electronegativity variations among different non-metal elements would also bring some potential in the modulations of e-DA and metal valence for tuning the performances.In this review,we summarize the recent developments of the many different anion-mixed transition metal compounds(e.g.,nitrides,halides,phosphides,chalcogenides,oxyhydroxides,and borides/borates)for efficient water electrolysis applications.First,we have introduced the general information of water-splitting and the description of anion-mixed electrocatalysts and highlighted their complementary functions of mixed anions.Furthermore,some latest advances of anion-mixed compounds are also categorized for hydrogen and oxygen evolution electrocatalysis.The rationales behind their enhanced electrochemical performances are discussed.Last but not least,the challenges and future perspectives are briefly proposed for the anion-mixed water dissociation catalysts.

AgPdCo hollow nanospheres electrocatalyst with high activity and stability toward the formate electrooxidation

The widespread commercial application of direct formate fuel cell(DFFC)is limited by the lack of efficient electrocatalysts for the formate oxidation reaction(FOR).AgPdCo hollow nanospheres(H-NSs)with jagged surfaces are successfully synthesized via a facile method involving the wet-chemical synthesis of AgPdCo nanospheres(NSs)and galvanic replacement reaction between Pd salt and AgPdCo NSs.Surpassing Ag_(30)Pd_(69)Co_(1) NSs and most of previously reported electrocatalysts,Ag_(9)Pd_(90)Co_(1) H-NSs exhibit extremely high FOR activity with a peak current density of 3.08 A·mg_(Pd)^(−1).Apart from the competitive activity,Ag_(9)Pd_(90)Co_(1) H-NSs show greatly improved chronoamperometric and cycling stability,whereby the current density retains about 0.24 A·mg_(Pd)^(−1) after 3,600 s electrocatalysis and the mass activity maintains 54.06%of the initial value after 500 cycles.The unique hollow nanosphere and synergistic effect are responsible for the enhanced activity and stability.This study will provide new clues for the development of outstanding electrocatalysts.

Fourier-Besov空间中双极型漂移-扩散方程的稳态极限

本文证明一类耗散方程{n_(t)^(∈)(-△)^(θ/2)n^(∈)+↓△·(n^(∈)↓△Ф^(∈)=0,(x,t)∈R^(d)×(0,∞),c_(t)^(∈)(-△)^(θ/2)c^(∈)+↓△·(c^(∈)↓△Ф^(∈)=0,(x,t)∈R^(d)×(0,∞),1/cφ_(t)^(∈)=(-△)^(θ/2)φ^(∈)+n^(∈)-c^(∈),(x,t)∈R^(d)×(0,∞),(n^(∈),c^(∈),φ^(∈))|t=0-(n_(0),c_(0),φ_(0),x∈R^(d)收敛(e→+∞)到双极型漂移-扩散方程{n_(t)+(-△)^(θ/2)n+↓△·(n↓△φ)=0,(x,t)∈R^(d)×(0,∞),c_(t)+(-△)^(θ/2)c+↓△·(c↓△φ)=0,(x,t)∈R^(d)×(0,∞),0=(-△)^(θ/2)φ+n-c,(x,t)∈R^(d)×(0,∞),(n,c)|t=0=(n_(0),c_(0),x∈R^(d),其中θ∈(1,2]和d≥3.确切地说,当p、q和θ满足一定的条件且初值满足(n_(0),c_(0)∈FB_(q,∞)^(2-2θ+d-d/q(R^(d)×FB_(q,∞)^(2-2θ+d-d/q*R^(d),φ_(0)∈FB_(q,∞)^(2-θ+d0d/q)(R^(d)∩FB_(1,)^(2-θ)(R^(d),本文利用Fourier局部化技巧和Littlewood-Paley分解理论证明了,若ε→+∞,则在Fourier-Besov空间中,(n^(∈),c^(∈))关于时间变量一致收敛到(n,c).