Comment on Altaf et al. Non-Thermal Plasma Reduction of Ag⁺ Ions into Silver Nanoparticles in Open Atmosphere under Statistically Optimized Conditions for Biological and Photocatalytic Applications. Materials 2022, 15, 3826

Altaf et al. recently published in Materials, 2022; 15(11), 3826, about the synthesis of silver nanoparticles (AgNPs) using the non-thermal plasma reduction of AgNO₃ salt and performed statistical optimization for the reaction conditions, i.e., (A) the concentration of a stabilizing agent, mM (B) concentration of AgNO₃ salt, mM and (C) the reaction time, mins. We would like to point out that their writing on the statistical analysis (Box-Behnken response surface methodology for predicting the size of the nanoparticles) is not complete and, therefore, cannot be independently checked by the readers. The problems found in their report are as follows: the hard-to-find actual value of the uncoded units; a dubious claim about the middle levels of variable B (salt concentration); inconsistency in using coded vs. uncoded units in the table vs. the regression equation; and three center points with identical conditions give a dissimilar prediction of results. These serious issues need to be clarified and revised, as well as several writing errors, in order to uphold the standard of scientific publications.