# Eppur si riscalda -- and yet, it (just) heats up: Further Comments on "Quantifying hot carrier and thermal contributions in plasmonic photocatalysis"

## TL;DR

This paper critically re-evaluates claims of non-thermal effects in plasmonic photocatalysis, highlighting measurement inaccuracies and technical flaws that favor conventional thermal explanations over novel mechanisms.

## Contribution

It provides a detailed critique of previous experimental claims, emphasizing the importance of accurate temperature measurement and proper data analysis in distinguishing thermal from non-thermal effects.

## Key findings

- Incorrect temperature measurements led to false claims of non-thermal effects.
- Identified flaws in experimental setup and data analysis in prior studies.
- Conventional theory sufficiently explains observed phenomena without invoking new mechanisms.

## Abstract

Our Comment [Sivan et al., Science 2019] (as well as its longer version [Dubi, Un, & Sivan, ArXiv 2019], and the supporting theoretical studies [Dubi and Sivan, ArXiv 2018]) on recent attempts to distinguish thermal and non-thermal ("hot carrier") contributions to plasmon-assisted photocatalysis [Zhou et al., Science 2018] initiated a re-evaluation process of previous literature on the topic within the nano-plasmonics and chemistry communities. The Response of Zhou et al. attempts to defend the claims of the original paper. In this manuscript, we show that the Response presents additional data that further validates our central criticism: inaccurately measured temperatures (that are lower than the actual temperature of the catalyst) led Zhou et al. to incorrectly claim conclusive evidence of non-thermal effects. We identify flaws in the experimental setup (e.g. the use of the default settings for the thermal camera and incorrect positioning of the thermometer) that may have led Zhou et al. to make such claims. We further show that the Response contains several factual errors and does not address the technical problems we identified with the data acquisition in [Zhou et al., Science 2018]. We demonstrate that both the Response and the original paper contain additional faults, for example, in the power determination and in the normalization of the rate to the catalyst volume, and exhibit misconceptions regarding the thermo-optic response of metal nanostructures. The burden of proof required by the proposal of a novel physical mechanism has simply not been met, especially when the existing data can be modeled exquisitely by conventional theory.