Huiqiong Wu

Cation Tuning toward the Inference of the Gelation Behavior of Supramolecular Gels.

We serendipitously discovered that the tripeptide Asp–Phe–Phe trifluoroacetic acid salt (hereafter abbreviated as β-AspFF) formed a reversible thermotropic gel in chloroform solution (at temperatures higher than the boiling point of chloroform), and a stable gel in toluene solution (at equal to or lower than the room temperature). Experimental results indicate that doping metal ions into β-AspFF toluene gels can trigger morphological variations in the gel skeleton, thereby increasing gel volume and inducing the collapse of organogels. Investigation on the cation-tuned gelation behavior of β-AspFF can be used to elucidate heating-induced gel collapse (of normal gel) or reverse thermotropic gelation as well as select carbamide and acetamide as activators of β-AspFF gels in chloroform solution at room temperature.

In Situ Fabrication of Defective CoNx Single Clusters on Reduced Graphene Oxide Sheets with Excellent Electrocatalytic Activity for Oxygen Reduction

A facile one-step strategy for anchoring defective CoNx single clusters on partly reduced graphene oxide (RGO) is constructed to significantly improve the catalytic performance of non-noble metal complexes toward oxygen reduction reaction (ORR). Sequent loading with trace amounts of metal-free porphyrin and Co2+ in RGO can dramatically enhance both the half-wave potential and the peak current density. Intriguingly, the RGO/P/2Co single cluster exhibits the best ORR catalytic performance with the half-wave potential of 0.834 V, extremely approaching that of commercial Pt/C (0.836 V). This half-wave potential surpasses most of the reported half-wave potentials of RGO supported non-noble metal ORR catalysts through low-temperature synthesis. Furthermore, the as-prepared RGO/P/2Co delivers a peak current density of 1.3 times higher than that of Pt/C at the same loading, together with a high mass activity of 2.76 A mgCo-1. During the durability test, a cathodic current loss less than 10% is recorded after 8000 continuous potential cycles. Insights into this successful example will be conducive to the development of elegant routes for constructing metal nitrogen (MN)-based ORR catalysts with high efficiency, outstanding stability, and excellent selectivity.

Pb2+-specific metallohydrogel based on tryptophan-derivatives: preparation, characterization, multi-stimuli responsiveness and potential applications in wastewater and soil treatment

A novel Pb2+-specific metallohydrogel HAIP–Pb was synthesized. HAIP–Pb possesses multi-stimuli responsiveness, including to pH, temperature, etc. Various measurements were performed to gain insights into the mechanism of gelation. The HAIP gelator can gel Pb2+ and simultaneously adsorb toxic dyes. Intriguingly, HAIP can cause gelation of soil containing Pb2+ ions.

Designing isometrical gel precursors to identify the gelation pathway for nickel-selective metallohydrogels

Two novel multi-responsive metallohydrogels, namely, 2-PF-Ni and 3-PF-Ni, were successfully constructed from phenylalanine derivatives. The 2-PF gelator shows specific responses to Ni2+; particularly, 2-PF-Ni is lavender colored, which has been rarely reported among hydrogels triggered by Ni2+. 3-PF-Ni is light green and exhibits perfect thixotropy. This paper provides insights into the gelation mechanisms of these two metallogels.

Encapsulation of nanocrystals with responsive gels for spatial optical identification

Abstract A tripeptide (β-AspFF) gelator was designed and synthesised using solid-phase peptide synthesis. The as-prepared gelator formed a stable and clear multi-responsive gel in toluene solution. Encapsulating the quantum dots with β-AspFF effectively increased stability and antioxidisation ability which are beneficial for optical identification. Graphical abstract

Supramolecular bimetallogels: a nanofiber network for bimetal/nitrogen co-doped carbon electrocatalysts

This paper reports a rational strategy using ‘supramolecular bimetallogel’ as a template to synthesize a series of bimetal (Fe–Co, Fe–Ni or Fe–Mn)/nitrogen co-doped carbon electrocatalysts for ORR with excellent performance. The bimetallogel nanofiber network serves as both bimetal and N sources as well as host matrix for the commercially available carbon. Thermal treatment of the bimetallogels enables homogenous in situ doping of the bimetal and N, affording bimetal/N co-doped carbon catalysts.