Reaction Pathway of the Hydrothermal Synthesis of AgCuO₂ from In Situ Time-Resolved X-ray Diffraction

Abstract

AgCuO 2 is an interesting semiconductor oxide with appealing optical and electronic properties.While the oxide has been synthesized in bulk by different approaches, no study on the formation mechanism has been carried out to date. We present an in situ time-resolved X-ray diffraction 2 study of the hydrothermal synthesis of AgCuO 2 from AgO and CuO. The effects of reaction pH and temperature on the reaction pathways and products have been studied. While pH is a key parameter for the successful synthesis of AgCuO 2 , temperature affects mainly the reaction kinetics. A reaction pathway is proposed that involves a series of dissolution-precipitation reactions, mediated by Cu and Ag hydroxy complexes. Finally, we have compared different approaches to obtain the reaction activation energy, which was calculated to be 70.6±5.1 kJ/mol. Nevertheless, our results show that new models need to be developed for the type of reaction presented here.

Real-Time Atomic-Scale Structural Analysis Resolves the Amorphous to Crystalline CaCO3 Mechanism Controversy

“…The explanation that the bond lengths in the incipient material shift with the precipitation mechanism is a more informed, and perhaps useful, metric with implications beyond calcite formation. This lattice parameter behavior was also observed in many other systems, such as in AgCuO 2 , BaTiO 3 , rhodochrosite (MnCO 3 ), and hematite (α-Fe 2 O 3 ) formations, − and this analysis method will provide similar insights into these diverse systems, especially the mechanisms of crystallization from amorphous material to incipient nuclei to fully established crystals.…”

Exploration of anion effects in solvothermal synthesis using in situ X-ray diffraction

“…Most studies have been focused on a single chemical system/product with exploration of select parts of the relevant parameter space. Thorough work has been presented on the structure-directing effect of additives in synthesis of CuPd nanoparticles, 24 BaTiO 3 , 25,26 AgCuO 2 , 27 YMnO 3 , 28 and NaNbO 3 , 29 TiO 2 growth control with and without surfactants, 30,31 product dependence on reaction temperature, time, precursor water content and pH in synthesis of In and Ga based materials, 32,33 complex stoichiometry/ coordination of W and Nb oxides, 34 and phase control, crystallite morphology, magnetic properties of SrFe 12 O 19 , 35 and the formation mechanism and attainable stoichiometry of high entropy alloy nanoparticles. [36][37][38][39] In an attempt to highlight and generalize trends for relevant synthesis parameters, we have previously studied the redox chemistry of five common solvents at reaction temperatures between ambient and 450 1C.…”

n-ZnO/Out-of-Stoichiometry p-CuCrO2 Diodes for Efficient and Low-Cost Transparent Electronic Applications

“…The transparent p−n junctions fabricated using such techniques showed a rectification ratio, I on /I off , with the highest value ever reported being 120 at ±5 V. 54 On the other hand, different works reported the fabrication of CuCrO 2 /ZnO-based p−n junctions by chemical routes, and a summary of the obtained results is reported in Table 1. The use of solution-based processes implies various fabrication advantages, such as the reduction of the used deposition temperature, ambient pressure, and affordable surface scalability, 55 both promising aspects for the industrialization of such devices. Nevertheless, the rectification ratio obtained is 1 order of magnitude lower than for physical deposition methods.…”