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[Display omitted] • Polycrystal C-HK(Cu/Ni) catalyst is derived from bimetal HKUST-1 via partial reduction. • Dispersed NiO/Cu/CuO on graphitic porous C engineers interfacial catalytic synergy. • Mesoporous C-HK(Cu/Ni) quickens adsorption and promotes catalytic activity for 4-NP. • C-HK(Cu/Ni) exhibits 3 ∼ 16 times higher catalytic activity for 4-NP reduction than current catalysts. • C-HK(Cu/Ni) possesses high stability and durability after six consecutive cycles. The novel Cu-based bimetal polycrystal@carbon (C-HK(Cu/M)) composites derived from metal (Ni, Zn and Co) in-situ substituted Cu-based HKUST-1 were successfully fabricated by partial reduction strategy and employed for the reduction of 4-nitrophenol (4-NP). Systematic characterization demonstrated that Ni showed stronger orbital hybridization with Cu than Zn and Co, thereby significantly improving the catalytic properties of the C-HK(Cu/Ni) composite. The presence of Ni in HKUST-1 efficiently inhibited the reduction of adjacent Cu clusters, leading to the generation of unique polycrystal NiO/Cu/CuO nanohybrids (2.4–8.0 nm) with high dispersion (Cu exposure reaching 88.5%). While, the MOF ligands were catalyzed by doping Ni into the conductive and porous carbons, and finally engineered interfacial synergistic catalysis for enhancing the kinetics and stability for the reduction of 4-NP. The porous support accelerated 4-NP diffusion and adsorption in the composite, and as a consequence, the surrounding polycrystal nanohybrids on conductive carbon were responsible for producing hydrogen reducing species for 4-NP reduction. Therefore, C-HK(Cu/Ni) exhibited ultrafast kinetics and turnover frequency (TOF) for 4-NP reduction, which were up to 179 and 14 times higher than parent C-HK(Cu), surpassing the current state-of-the-art noble metal catalysts. Moreover, the activity of C-HK(Cu/Ni) was evaluated for six consecutive runs with minimal loss, demonstrating the high reusability and practicability of the catalyst on an industrial scale. [ABSTRACT FROM AUTHOR]

Heavy-duty diesel trucks (HDDTs) comprise a key source of road transport emissions and energy consumption worldwide mainly due to the growth of road freight traffic during the last two decades. Addressing their air pollutant and greenhouse gas emissions is therefore required, while accurate emission factors are needed to logistically optimize their operation. This study characterizes real-world emissions and fuel consumption (FC) of HDDTs and investigates the factors that affect their performance. Twenty-two diesel-fueled, Euro IV to Euro VI, HDDTs of six different manufacturers were measured in the road network of the Hong Kong metropolitan area, using portable emission measurement systems (PEMS). The testing routes included urban, highway and mixed urban/highway driving. The data collected corresponds to a wide range of driving, operating, and ambient conditions. Real-world distance- and energy-based emission levels are presented in a comparative manner to capture the effect of after-treatment technologies and the role of the evolution of Euro standards on emissions performance. The emission factors' uncertainty is analyzed. The impact of speed, road grade and vehicle weight loading on FC and emissions is investigated. An analysis of diesel particulate filter (DPF) regenerations and ammonia (NH3) slip events are presented along with the study of Nitrous oxide (N2O) formation. The results reveal deviations of real-world HDDTs emissions from emission limits, as well as the significant impact of different operating and driving factors on their performance. The occasional high levels of N2O emissions from selective catalytic reduction equipped HDDTs is also revealed, an issue that has not been thoroughly considered so far. [ABSTRACT FROM AUTHOR]