Driven by the need for sustainably sourced catalysts and the use of reaction systems that generate environmentally benign by-products, the present study aimed to deposit stable, dispersed palladium (Pd) nanoparticles on the modified surfaces of granular macadamia nutshell (MNS) biomass for catalytic reduction of hexavalent chromium (Cr(VI)) to trivalent chromium (Cr(III)). Through wet impregnation with Pd(II) ions and subsequent hydrazine-mediated reduction to Pd(0), Pd nanoparticles were embedded in a scaffold of polyethyleneimine grafted on bleached MNS previously coated with a chemically bound layer of polyglycidyl methacrylate. Imagery from scanning electron microscopy showed the formation of different layers of the polymeric coating and dispersed palladium resulting from surface modification and palladium nanoparticle synthesis, respectively. X-ray diffraction analysis confirmed the formation of Pd on the modified MNS surface and suggested an estimated crystallite size of 5.0 nm. The supported nanoparticles exhibited catalytic activity in formic acid-mediated Cr(VI) reduction and showed promising stability with consecutive reuse. These findings set the stage for advanced studies into performance optimization.

在对可持续来源的催化剂的需求以及产生对环境无害的副产物的反应系统的使用的驱动下，本研究旨在将稳定，分散的钯（Pd）纳米颗粒沉积在颗粒澳洲坚果壳（MNS）生物质的改性表面上，以进行催化六价铬（Cr（VI））还原为三价铬（Cr（III））。通过用Pd（II）离子进行湿法浸渍，然后通过肼介导的还原成Pd（0），Pd纳米颗粒被嵌入聚乙烯亚胺的支架中，该支架接枝到已预先涂有聚甲基丙烯酸缩水甘油酯化学结合层的漂白MNS上。来自扫描电子显微镜的图像显示分别由表面改性和钯纳米颗粒合成导致的聚合物涂层和分散的钯的不同层的形成。X射线衍射分析证实了修饰的MNS表面上形成了Pd，并表明估计的微晶尺寸为5.0 nm。负载的纳米颗粒在甲酸介导的Cr（VI）还原中表现出催化活性，并在连续重复使用时显示出良好的稳定性。这些发现为性能优化的高级研究奠定了基础。