This research work is taken up to synthesize highly crystalline and ordered Ag@PtNPs core-shell nanoparticles (NPs) via a bio-inspired route using Psidium guajava leaves-extract with high ascorbic acid equivalent (284 /100 g fresh leaves). A short microwave exposure (900 W and 300 s) led to a quick formation of AgNPs-seed (25.7 nm avg). The seed was then subjected for a rapid growth (240 s) of Pt-shell (4.55 nm) which was synergized by bio-extract and microwave irradiation forming Ag@PtNPs. The graphite electrode was surface-modified using these NPs for electrocatalytic sensing of Pb(II) by square wave anodic stripping voltammetry. The electron transfer resistance of bare graphite was reduced by 1.2, 26, and 2.9 folds, respectively, with PtNPs, AgNPs, and Ag@PtNPs modification. The sensitivity of Ag@PtNPs/graphite electrode for Pb(II) sensing calculated against the electroactive area was about 4.5 and 20.2 folds higher than PtNPs/graphite and AgNPs/graphite electrodes at −0.43 V vs. Ag/AgCl and pH 5. The limit of detection was as low as 0.8 nM. The response of the sensor (max. 1.98 % variation in peak current) was almost invariant in the presence of co-ions (Cd(II), Cu(II) and Hg(II) from 0.25 to 10 μM). The sensor it could effectively determine Pb(II) from environmental water samples collected from river, domestic supply and sewage treatment plant.

这项研究工作是通过使用番石榴（Psidium guajava）通过生物启发的途径来合成高度结晶和有序的Ag @ PtNPs核壳纳米粒子（NP）。叶提取物具有较高的抗坏血酸当量（284/100 g新鲜叶子）。短暂的微波暴露（900 W和300 s）导致AgNPs种子（25.7 nm平均）的快速形成。然后使种子经历Pt壳（4.55 nm）的快速生长（240 s），通过生物提取和微波辐射协同作用，形成Ag @ PtNPs。使用这些NP对石墨电极进行表面改性，以通过方波阳极溶出伏安法对Pb（II）进行电催化传感。通过修饰PtNP，AgNP和Ag @ PtNPs，裸露的石墨的电子转移电阻分别降低了1.2倍，26倍和2.9倍。相对于Ag / AgCl和pH 5，在-0.43 V电压下，Ag @ PtNPs /石墨电极对Pb（II）感测的灵敏度相对于电活性区域分别约为PtNPs /石墨和AgNPs /石墨电极的4.5和20.2倍。检测限低至0.8 nM。传感器的响应（最大1.98％峰值电流变化）在存在共离子（0.25至10μM的Cd（II），Cu（II）和Hg（II））时几乎不变。该传感器可以有效地从河流，家庭供水和污水处理厂收集的环境水样中确定Pb（II）。