The hydrogenation of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) is an effective and cost-competitive procedure to change waste into valuables. With the purpose of designing efficient and green catalysts to convert 4-NP, we adopt halloysite nanotubes (HNTs), a resource-rich and eco-friendly clay mineral material, as CoNi alloy nanoparticles support in this study. The HNTs used have been increased the surface roughness (defined as rHNTs) through the etching process. Thereafter, a series of ultrafine CoNi alloy nanoparticles (1.2 ∼ 1.4 nm) anchored onto rHNTs (CoNi/rHNTs, where x represents the molar percentage of Co to total metal elements) are successfully synthesized via a simple one-pot approach. Benefitting from the positive synergy of Co and Ni bimetals and the powerful metal-support interaction, CoNi/rHNTs catalyst (8.55 wt% total actual metal loading) exhibits the best catalytic performance for 4-NP degradation with a conversion efficiency of 99 % within 4 min at 298 K, and meanwhile a high turnover frequency (TOF) of 1.16 × 10 mmol mg min is achieved with the rate constant of 1.09 min. Of note, CoNi/rHNTs also show excellent degradation performance towards two other nitrophenol isomers (2-nitrophenol and 3-nitrophenol).

中文翻译：

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超细 CoNi 合金纳米粒子锚定在表面粗糙埃洛石纳米管上，用于 4-硝基苯酚的高效催化氢化


4-硝基苯酚 (4-NP) 氢化为 4-氨基苯酚 (4-AP) 是一种有效且具有成本竞争力的变废为宝的方法。为了设计高效、绿色的催化剂来转化4-NP，我们采用埃洛石纳米管（HNT）这种资源丰富且环保的粘土矿物材料作为CoNi合金纳米颗粒的支撑。所使用的 HNT 通过蚀刻工艺增加了表面粗糙度（定义为 rHNT）。此后，通过简单的一锅法成功合成了一系列锚定在rHNTs上的超细CoNi合金纳米颗粒（1.2∼1.4 nm）（CoNi/rHNTs，其中x代表Co占总金属元素的摩尔百分比）。受益于Co和Ni双金属的正协同作用以及强大的金属-载体相互作用，CoNi/rHNTs催化剂（总实际金属负载量为8.55 wt%）表现出最佳的4-NP降解催化性能，4内转化效率高达99% min 在 298 K 下，同时以 1.09 min 的速率常数实现了 1.16 × 10 mmol mg min 的高周转频率 (TOF)。值得注意的是，CoNi/rHNT 对其他两种硝基苯酚异构体（2-硝基苯酚和 3-硝基苯酚）也表现出优异的降解性能。