Shengsheng Cui

Highly Efficient and Stable Water-Oxidation Electrocatalysis with a Very Low Overpotential using FeNiP Substitutional-Solid-Solution Nanoplate Arrays

The development of efficient water-oxidation electrocatalysts based on inexpensive and earth-abundant materials is significant to enable water splitting as a future renewable energy source. Herein, the synthesis of novel FeNiP solid-solution nanoplate (FeNiP-NP) arrays and their use as an active catalyst for high-performance water-oxidation catalysis are reported. The as-prepared FeNiP-NP catalyst on a 3D nickel foam substrate exhibits excellent electrochemical performance with a very low overpotential of only 180 mV to reach a current density of 10 mA cm-2 and an onset overpotential of 120 mV in 1.0 m KOH for the oxygen evolution reaction (OER). The slope of the Tafel plot is as low as 76.0 mV dec-1 . Furthermore, the long-term electrochemical stability of the FeNiP-NP electrode is investigated by cyclic voltammetry (CV) at 1.10-1.55 V versus reversible hydrogen electrode (RHE), demonstrating very stable performance with negligible loss in activity after 1000 CV cycles. This present FeNiP-NP solid solution is thought to represent the best OER catalytic activity among the non-noble metal catalysts reported so far.

A Copper Porphyrin‐Based Conjugated Mesoporous Polymer‐Derived Bifunctional Electrocatalyst for Hydrogen and Oxygen Evolution

Scalable and robust catalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are required for the implementation of water splitting technologies as a globally applicable method of producing renewable hydrogen. Herein, we report nitrogen-enriched porous carbon materials containing copper/copper oxide, derived from copper porphyrin-based conjugated mesoporous polymers (CMPs), as a bifunctional catalyst for both HER and OER. These catalysts have a high surface area, unique tubular structure, and strong synergistic effect of copper/copper oxide and porous carbons, resulting in excellent performance for water splitting. Under optimal conditions, the catalyst exhibits a quite low overpotential for OER (350 mV to reach 1.0 mA cm(-2) and 450 mV to reach 10 mA cm(-2) ) in alkaline media, which places it among the best copper-based water oxidation catalysts reported in the literature. Furthermore, the catalyst shows good catalytic activity for HER at a low overpotential (190 mV to reach 1.0 mA cm(-2) ) as well as a high current density (470 mV to reach 50 mA cm(-2) ). The results suggest that hybridized copper/carbon materials are attractive noble-metal-free catalysts for water splitting.

A novel symmetrically multifunctionalized dodecamethoxy-cycloparaphenylene: synthesis, photophysical, and supramolecular properties

In the present study, we report the synthesis of a novel symmetrically multifunctionalized cycloparaphenylene (CPP), dodecamethoxy-[9]CPP (ring[9]arene), through nickel-mediated macrocyclization and subsequent reductive aromatization reactions. The electron-donating methoxy groups were introduced onto the curved precursor at an early stage to avoid the problem of non-selective functionalization of CPPs. Compared to [9]CPP, the present dodecamethoxy-[9]CPP shows a significant red shift (>73 nm) in the fluorescence spectrum. In addition, theoretical calculations revealed its increased torsion angles and ring strain (71.01 kcal mol−1) compared with its unsubstituted counterpart.

A Three‐Dimensional Capsule‐like Carbon Nanocage as a Segment Model of Capped Zigzag [12,0] Carbon Nanotubes: Synthesis, Characterization, and Complexation with C70

Herein we report the synthesis and photophysical and supramolecular properties of a novel three-dimensional capsule-like hexa-peri-hexabenzocoronene (HBC)-containing carbon nanocage, tripodal-[2]HBC, which is the first synthetic model of capped zigzag [12,0] carbon nanotubes (CNTs). Tripodal-[2]HBC was synthesized by the palladium-catalyzed coupling of triboryl hexabenzocoronene and L-shaped cyclohexane units, followed by nickel-mediated C-Br/C-Br coupling and subsequent aromatization of the cyclohexane moieties. The physical properties of tripodal-[2]HBC and its supramolecular host-guest interaction with C70 were further studied by UV/Vis and fluorescence spectroscopy. Theoretical calculations revealed that the strain energy of tripodal-[2]HBC was as high as 55.2 kcal mol-1 .

Improving the water splitting performance of nickel electrodes by optimizing their pore structure using a phase inversion method

Porous nickel electrodes were fabricated by the phase inversion tape casting method. The as-prepared nickel electrode contained finger-like straight open pores with an average diameter of ∼100 μm and smaller pores with an average diameter of 1–3 μm in the walls. When used as an anode for the oxygen evolution reaction (OER), the porous nickel electrode shows high catalytic activity, reaching a catalytic current density of 10 mA cm−2 under an overpotential of only 300 mV in 1.0 M KOH. It also exhibited excellent performance for the hydrogen evolution reaction (HER), resulting in a current density of 10 mA cm−2 under an overpotential of 125 mV in the same electrolyte. For both OER and HER, the electrode shows great catalytic stability and much better catalytic performance than commercial nickel foam. Moreover, an alkaline electrolyzer using identical porous nickel electrodes as both the anode and cathode required a cell voltage of only 1.65 V to reach 10 mA cm−2 for overall water splitting. The improved electrocatalytic performance of the electrode can be attributed to its unique dual-pore structure.