Well-dispersed gold nanoparticles (Au NPs) anchored by polymeric three-dimensional hydrogels for catalysis have received great attention, especially in aqueous-phase catalysis. In this study, thiol-functionalized chitosan poly(protic ionic liquids) hydrogel (TCPPILH) is delicately designed and prepared as a selective support material to anchor Au NPs by taking advantages of Au-thiol chemistry and facile preparation of protic ionic liquids (PILs). The TCPPILH was successfully synthesized by a protonation reaction of chitosan with 3-mercaptopropionic acid (MPA) and mercaptosuccinic acid (MSA) in water, and followed by shaping in ethanol coagulation bath via solution-gelation transition, and the properties can be facilely adjusted by changing the feed ratio of MPA and MSA. It is found that the TCPPILH can act as a selective support for adsorption of Au³⁺ ions, and a maximal anchoring capacity for Au NPs could reach up to 151.5 mg/g. The as-prepared TCPPILH@Au NPs catalysts were systematically characterized by FTIR, XPS, SEM, TEM, XRD and ICP-OES analysis, and the findings demonstrated that the TCPPILH could effectively inhibit the agglomeration of Au NPs (ca. 4.20 nm in diameter). As a proof of concept, hydrogenation of water pollutes, such as 4-nitrophenol and azo dyes with NaBH₄ as reductant was selected as model applications, and the results indicated that TCPPILH@Au NPs catalysts exhibited high catalytic activity and satisfactory reusability.

Graphical abstract

Thiol-functionalized chitosan poly(protic ionic liquids) hydrogel (TCPPILH) was delicately designed and prepared as a selective support material to adsorb Au³⁺ and anchoring Au NPs by taking advantages of Au-thiol chemistry and facile preparation of protic ionic liquids (PILs). This TCPPILH@Au NPs catalysts exhibited desired catalytic activity for the hydrogenation of 4-nitrophenol and azo dyes in water.

中文翻译：

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硫醇功能化壳聚糖聚（质子离子液体）水凝胶选择性锚定金纳米粒子用于水催化

由聚合物三维水凝胶固定的分散良好的金纳米粒子 (Au NPs) 用于催化受到了极大的关注，特别是在水相催化中。在这项研究中，硫醇功能化的壳聚糖聚（质子离子液体）水凝胶（TCPPILH）被精心设计和制备作为选择性支持材料，通过利用 Au-硫醇化学和质子离子液体（PILs）的简便制备来锚定 Au NPs . TCPPILH由壳聚糖与3-巯基丙酸（MPA）和巯基丁二酸（MSA）在水中质子化反应成功合成，然后在乙醇凝固浴中通过溶液-凝胶化转变成型，其性能可通过以下方式轻松调节改变 MPA 和 MSA 的进料比。³⁺离子，Au NPs 的最大锚定能力可达 151.5 mg/g。通过 FTIR、XPS、SEM、TEM、XRD 和 ICP-OES 分析对所制备的 TCPPILH @ Au NPs 催化剂进行了系统表征，结果表明 TCPPILH 可以有效抑制 Au NPs（直径约 4.20 nm）的团聚). 作为概念验证，我们选择以 NaBH _{4作为还原剂对水污染物（例如 4-硝基苯酚和偶氮染料）进行加氢作为模型应用，结果表明 TCPPILH} @ Au NPs 催化剂表现出高催化活性和令人满意的可重复使用性。

图形概要

硫醇官能化壳聚糖聚（质子离子液体）水凝胶（TCPPILH）是精心设计和制备的选择性支持材料，通过利用 Au-硫醇化学和质子离子液体（PILs）的简便制备来吸附 Au 3+ 和^锚定 Au NPs ). 这种 TCPPILH@Au NPs 催化剂对 4-硝基苯酚和偶氮染料在水中的氢化表现出理想的催化活性。