Theoretical calculations unveil that the formation of Os-OsSe2 heterostructures with neutralized work function (WF) perfectly balances the electronic state between strong (Os) and weak (OsSe2) adsorbents and bidirectionally optimizes the hydrogen evolution reaction (HER) activity of Os sites, significantly reducing thermodynamic energy barrier and accelerating kinetics process. Then, heterostructural Os-OsSe2 is constructed for the first time by a molten salt method and confirmed by in-depth structural characterization. Impressively, due to highly active sites endowed by the charge balance effect, Os-OsSe2 exhibits ultra-low overpotentials for HER in both acidic (26 mV @ 10 mA cm-2) and alkaline (23 mV @ 10 mA cm-2) media, surpassing commercial Pt catalysts. Moreover, the solar-to-hydrogen device assembled with Os-OsSe2 further highlights its potential application prospects. Profoundly, this special heterostructure provides a new model for rational selection of heterocomponents.

Work-function-induced Interfacial Built-in Electric Fields in Os-OsSe2 Heterostructures for Active Acidic and Alkaline Hydrogen Evolution.

Borophene and MoS2 are promising two-dimensional functional materials because of the advantage of high specific surface. However, due to the instability and inert surface factors, they do not perform well...

Catalytic Properties of Borophene/MoS2 Heterojunctions for Hydrogen Evolution Reaction under Different Stacking Conditions

The utilization of nanostructured materials as efficient catalyst for several processes has increased tremendously, and carbon-based nanostructured materials encompassing fullerene and its derivatives have been observed to possess enhanced catalytic activity when engineered with doping or decorated with metals, thus making them one of the most promising nanocage catalyst for hydrogen evolution reaction (HER) during electro-catalysis. Prompted by these, and the reported electrochemical, electronic and stability advantage, an attempt is put forward herein to inspect the metal encapsulated, doped, and decorated dependent HER activity of C24 engineered nanostructured materials as effective electro-catalyst for HER. Density functional theory (DFT) calculations have been utilized to evaluate the catalytic hydrogen evolution reaction activity of four proposed bare systems: fullerene (C24), calcium encapsulated fullerene (CaencC24), nickel-doped calcium encapsulated fullerene (NidopCaencC24), and silver decorated nickel-doped calcium encapsulated (AgdecNidopCaencC24) engineered nanostructured materials at the TPSSh/GenECP/6-311+G(d,p)/LanL2DZ level of theory. The obtained results divulged that, a potential decrease in energy gap (Egap) occurred in the bare systems, while a sparing increase was observed upon adsorption of hydrogen onto the surfaces, these surfaces where also observed to maintain the least EH-L gap while the AgdecNidopCaencC24 surface exhibited an increased electrocatalytic activity when compared to others. The results also showed that the electronic properties of the systems evinced a correspondent result with their electrochemical properties, the Ag-decorated surface also exhibited a proficient adsorption energy [Formula: see text] and Gibb's free energy (ΔGH) value. The engineered Ag-decorated and Ni-doped systems were found to possess both good surface stability and excellent electro-catalytic property for HER activities. 

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Electrocatalytic activity of metal encapsulated, doped, and engineered fullerene-based nanostructured materials towards hydrogen evolution reaction

Underpotential deposition promoting low Pt loading on MoO2/MoS2 heterostructure towards wide pH green hydrogen evolution

Interface engineering is an effective strategy to regulate surface properties and improve the catalytic activities of materials. Here we develop an interface engineered core-shell structure [email protected] catalyst, which only requires 50 mV to realize current density of 10 mA/cm2 with a low Tafel slope of 51.1 mV/dec in 1 M KOH. Density functional theory (DFT) simulations indicate the [email protected] interface exhibits optimal H* adsorption energy (0.06 eV) compared with pure-phased CoP (0.26 eV) and pure-phased FeP (−0.18 eV), which is attributed to the significantly electronic structure modulation of Fe and Co atoms at the interface domain. Furthermore, the assembled NiFe [email protected]3O4/NF||[email protected]/NF electrolyzer only demands the voltages of 1.50 and 1.70 V to achieve 10 and 100 mA/cm2 under 1 M KOH. The electrolyzer also exhibits considerable catalytic performance in alkaline seawater electrolyte. What's more, it also can be driven by a commercial Si solar panel under AM 1.5 G 100 mW/cm2 illumination. The regulation of interface-effect paves a novel avenue for constructing high-performance catalysts for hydrogen production. 

Interfacial electronic structure modulation of CoP nanowires with FeP nanosheets for enhanced hydrogen evolution under alkaline water/seawater electrolytes

Interfacial electronic structure modulation of Pt-MoS2 heterostructure for enhancing electrocatalytic hydrogen evolution reaction

Developing efficient and low-cost non-noble metal catalysts for the oxygen evolution reaction (OER) is important for hydrogen production through water electrolysis. Herein, Fe doped NiS nanosheets directly grown on conductive carbon fiber paper (Fe–NiS@CFP) were fabricated through a two-step hydrothermal process. The microstructure, interface and electronic states of the prepared sample were modulated by Fe doping, exhibiting small internal and interface charge-transfer resistance. Benefiting from these factors, Fe–NiS@CFP shows superior electrocatalytic performance with an overpotential of 275 mV at 100 mA cm−2 and maintains the activity for at least 50 h as a working electrode for the OER. This work may provide insights into the design and fabrication of non-noble metal sulfide electrocatalysts.

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Fe doped NiS nanosheet arrays grown on carbon fiber paper for a highly efficient electrocatalytic oxygen evolution reaction

Insights into the Role of Protonation in Covalent Triazine Framework-Based Photocatalytic Hydrogen Evolution

Quasi-two-dimensional (2D) organic-inorganic hybrid tin perovskites have emerged as promising alternatives to lead-based perovskites in thin-film photovoltaics because of their reduced toxicity and improved stability. However, the undesired small n-value 2D phases and disordered crystal orientation enormously restrict the efficiency of quasi-2D tin perovskite solar cells (PSCs) due to uncontrollable nucleation and crystal growth processes. Here, we propose a mixed pseudo-halide anion engineering approach by using acetate (Ac−) and tetrafluoroborate (BF4−) anions to make quasi-2D Ruddlesden-Popper perovskites with a target formula of PEA2FA4Sn5I16. We find that the mixed Ac− and BF4− anions can not only promote homogeneously distributed PEA+ cations in the precursor by effectively breaking the PEA+···PEA+ stacking but also retard the crystallization process by coordinating with unbonded SnI2, thereby, significantly reducing small n-value 2D phases, improving the crystal orientation, and suppressing the Sn2+ oxidation. The resulting PSC exhibits up to 9% power conversion efficiency and 400 h stability. 

Pseudo-halide anion engineering for efficient quasi-2D Ruddlesden-Popper tin perovskite solar cells

Perovskite quantum dot (QD) has emerged as a promising material for photovoltaics with its superior stability compared to their three-dimensional bulk counterparts, owing to its thermodynamically stabilized photoactive phase. However, ligand management on perovskite QD surfaces is extremely difficult due to the ionic nature of the perovskite lattice, which often leads to either incomplete removal of the native insulating ligands or formation of trap states during the ligand-exchange process, greatly hampering the photovoltaic performances. In this work, we report an ion-assisted ligand-exchange method for FAPbI3 QDs using A-OAc (A = formamidinium (FA+), guanidinium (GA+), and phenethylammonium (PEA+), OAc = acetate), with the A+ and OAc– ions promoting the removal of native long-chain insulating ligands. The more complete ligand exchange results in dense and well-oriented packing of QDs, together with the enhancement of electronic coupling and charge transport across QDs. In addition, the A+ and OAc– ions can fill the surface A-/X-site vacancies, respectively, reducing the QD surface trap state density and hence suppressing charge recombination and iodide migration. The p–i–n inverted QD solar cells fabricated with this ligand-exchange method exhibit significant enhancement in short-circuit current density (JSC), reaching a PCE of 10.13%. Moreover, unencapsulated devices show impressive stabilities of more than 7300 h (10 months) storage time in a N2-filled glovebox. 

Hao Li

Papers

Interfacial electronic structure modulation of Pt-MoS2 heterostructure for enhancing electrocatalytic hydrogen evolution reaction

Fe doped NiS nanosheet arrays grown on carbon fiber paper for a highly efficient electrocatalytic oxygen evolution reaction

Insights into the Role of Protonation in Covalent Triazine Framework-Based Photocatalytic Hydrogen Evolution

Pseudo-halide anion engineering for efficient quasi-2D Ruddlesden-Popper tin perovskite solar cells

Ion-Assisted Ligand Exchange for Efficient and Stable Inverted FAPbI3 Quantum Dot Solar Cells