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Improving the low‐temperature water‐resistance of methane combustion catalysts is of importance for industrial applications and it is challenging. A stepwise strategy is presented for the preparation of atomically dispersed tungsten species at the catalytically active site (Pd nanoparticles). After an activation process, a Pd−O−W1‐like nanocompound is formed on the PdO surface with an atomic scale interface. The resulting supported catalyst has much better water resistance than the conventional catalysts for methane combustion. The integrated characterization results confirm that catalytic combustion of methane involves water, proceeding via a hydroperoxyl‐promoted reaction mechanism on the catalyst surface. The results of density functional theory calculations indicate an upshift of the d‐band center of palladium caused by electron transfer from atomically dispersed tungsten, which greatly facilitates the adsorption and activation of oxygen on the catalyst.

Pollution of water resources by antibiotics is a growing environmental concern. In this work, nanocomposites of g-C 3 N 4 @Ni−Ti layered double hydroxides (g-C 3 N 4 @Ni− Ti LDH NCs) with high surface areas were synthesized through an optimized hydrothermal method, in the presence of NH 4 F. Application of various characterization techniques unraveled that the prepared nanocomposites are composed of porous Ni−Ti LDH nanoparticles and hierarchical g-C 3 N 4 nanosheets. Further, these NCs were employed for photocatalytic and sonophotocatalytic removal of amoxicillin (AMX), as a model antibiotic, from aqueous solutions. In addition, sonocatalysis was performed. It was found out that the g-C 3 N 4 @Ni−Ti LDH NCs outperform their pure g-C 3 N 4 and Ni−Ti LDH components in photocatalytic degradation of AMX under visible light irradiation. Also, the following order was determined for efficiency of the three adopted processes: sonocatalysis < photocatalysis < sonophotocatalysis. Furthermore, variation of the sonophotocatalysis conditions specified 500 W light intensity, 9 s on/1 s off ultrasound pulse modem and 1.25 g/L g-C 3 N 4 -20@Ni−Ti LDH as the optimal conditions. In this way, optimization of the highly efficient sonophotocatalytic process resulted in 99.5% AMX degradation within 75 min. Moreover, a TOC analyzer was employed to estimate the rate of AMX degradation over the nanocomposites. In addition, formation of hydroxyl radicals ( • OH) on the surface of the g-C 3 N 4 -20@Ni−Ti LDH particles was approved using the terephthalic acid probe in photoluminescence (PL) spectroscopy. No significant loss was observed in the sonophotocatalytic activity of the nanocomposites even after five consecutive runs. Also, a plausible mechanism was proposed for the sonophotocatalysis reaction. In general, our findings can be considered as a starting point for synthesis of other g-C 3 N 4 -based NCs and application of the resultant nanocomposites to environmental remediation.