Role of carboxylates in the phase determination of metal sulfide nanoparticles
Role of carboxylates in the phase determination of metal sulfide nanoparticles
复制标题
羧酸盐在金属硫化物纳米颗粒物相测定中的作用
DOI：
10.1039/d3nh00227f
复制
发表时间：
2023
影响因子：
9.7
通讯作者：
Macdonald, Janet E.
中科院分区：
文献类型：
--
作者：
Shults, Andrey A.;Lu, Guanyu;Caldwell, Joshua D.;Macdonald, Janet E.
在胶体合成中控制纳米颗粒形状和尺寸的技术已经很成熟，但对前体相互作用及其对所得结晶相的影响了解甚少。在这里，我们表明，油酸酯，一个表面稳定的配体，是无处不在的合成，发挥了很大的作用时，硫脲作为硫源的各种金属硫化物纳米粒子的相选择的机制。气相和固相FTIR，13 C，和1H NMR研究表明，油酸和硫脲相互作用，产生油酰胺，促进硫脲的异构转变为硫氰酸铵，一种反应性较低的硫试剂。由于这些硫螯合反应，产生了缺硫和亚稳的纳米颗粒，这是四种不同金属的趋势：铜，铁，镍和钴。在低羧酸盐浓度下，粉末XRD表明形成了以下相：铜蓝（CuS）;硅镁矾（NiS 2）;菱镁矿（FeS1.3）、硼硅镁石（FeS1.3）、白铁矿（FeS 2）和黄铁矿（FeS 2）;以及碳硫铁矿（CoS 2）。在高油酸钠浓度下，这些相形成：蓝辉铜矿（CuS0.55），硫化镍（NiS），磁黄铁矿（FeS1.1），和jaipurite（CoS）。
Techniques are well established for the control of nanoparticle shape and size in colloidal synthesis, but very little is understood about precursor interactions and their effects on the resultant crystalline phase. Here we show that oleate, a surface stabilizing ligand that is ubiquitous in nanocrystal synthesis, plays a large role in the mechanism of phase selection of various metal sulfide nanoparticles when thiourea is used as the sulfur source. Gas and solid-phase FTIR, 13C, and 1H NMR studies revealed that oleate and thiourea interact to produce oleamide which promotes the isomeric shift of thiourea into ammonium thiocyanate, a less reactive sulfur reagent. Because of these sulfur sequestering reactions, sulfur deficient and metastable nanoparticles are produced, a trend seen across four different metals: copper, iron, nickel, and cobalt. At low carboxylate concentrations, powder XRD indicated that the following phases formed: covellite (CuS); vaesite (NiS2); smythite (FeS1.3), greigite (FeS1.3), marcasite (FeS2) and pyrite (FeS2); and cattierite (CoS2). At high sodium oleate concentration, these phases formed: digenite (CuS0.55), nickel sulfide (NiS), pyrrhotite (FeS1.1), and jaipurite (CoS).