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The palladized cell (Pd-cell) could be used as an efficient catalyst in catalyzing the degradations of a wide variety of environmental contaminants. Nevertheless, when the Pd NPs associate with the bacteria, the catalytic activity likely significantly affected by the biomass. Quantitative indicators that characterize of Pd-cell are necessary and little attention has been paid to investigate how the catalytic efficiency of Pd-cell is affected by the size and distribution of Pd NPs. To fill this gap, we explored the roles of the above-mentioned key factors on the performance of Pd-cell in catalyzing the degradations of two aromatic contaminants (nitrobenzene and p-chlorophenol) in two commonly used scenarios: (1) using Pd-cell as suspended catalyst in solution and (2) using Pd-cell as electrocatalyst directly coated on electrode. In scenario (1), the relationship of exposing area to Pd particle size and distribution factors was established. Based on theoretical estimation and catalytic performance analysis, the results indicated that adjusting the exposing area to a large value (9.3 ± 0.1 × 105 nm2 mg-1 Pd) was extremely effective for improving the catalytic activity of Pd-cell used as a suspension catalyst. In scenario (2), our results showed that the best electrocatalytic performances were achieved on the electrode decorated with Pd-cells with the largest NP size (54.3 ± 16.4 nm), which exerted maximum electrochemical active surface area (10.6 m2 g-1) as well as favorable conductivity. The coverage of deposited Pd NPs (>95%) on the cell surface played a crucial role in boosting the conductivity of biocatalyst, thus determining the possibility of Pd-cell as an efficient electrocatalyst. The findings of this study provide a guidance for the synthesis and application of Pd-cell, which enables the design of Pd-cell to be suitable for different catalysis systems with high catalytic performance.

Environmental attitude, value and awareness are widely believed to help reach the goal of cutting global food waste, but these psychological and cognitive factors are not always good predictors of wasteful behaviours. Notably, it is still unclear how the role of pro-environmental attitude (PEA) in reducing household food waste (HFW) changes with grocery shopping distance. To this end, using 7319 households survey data from China, this study investigates the moderating effect of shopping distance on the link between PEA and HFW behaviour. The results of Tobit regressions show that PEA is an important predictor of actual HFW behaviour in the absence of the constraint of shopping distance. However, the expansion of shopping distance will weaken the positive role of PEA in reducing HFW. It indicates that, due to the temporal and financial constraints generated by shopping distance, there is a certain degree of hypothetical deviation between the wasteful behaviours that individuals actually exhibit and their stated PEA. Our findings, from the perspective of the moderating effect of shopping distance, explain why some individuals deviate from their stated PEA in HFW behaviour, which provides a new insight into the generation of 'attitude-behaviour' gap. Therefore, policy interventions that merely enhancing environmental education may have limited effect on reducing food waste; instead, the promotion of citizen environmental ethics should be combined with efforts to improve the accessibility of retail infrastructures., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.