This work employed the attapulgite (ATP) clay as a potentially cost-effective mineral support and constructed a series of high-performance Ni-based catalysts for CO2 methanation through a multi-step synergistic strategy, including acid washing pretreatment, calcination temperature optimization, and promoter incorporation (La2O3, CeO2, and Co2O3). The effects of different preparation parameters on the structure and catalytic performance of the catalysts were systematically investigated. The results demonstrated that acid washing pretreatment effectively removed surface impurities from ATP, optimized the pore structure, and enhanced the accessibility of active sites. The calcination temperature at 400 degrees C enabled high NiO dispersion while preserving the structural stability of the support. Notably, the introduction of La2O3 as a promoter further refined the NiO crystallite size, strengthened metal-support interactions, and enriched surface basic sites and active oxygen species. As a result, the optimal catalyst, Ni-La2O3/A-ATP-400, achieved a CO2 conversion exceeding 50% at 300 degrees C, accompanied by a low apparent activation energy of 54.23 kJ/mol. In addition, it exhibited excellent CH4 selectivity (>90%) and good catalytic stability, maintaining high conversion during a 20 h time-on-stream test. Comprehensive characterization using N-2 physisorption, XRD, TEM, H-2-TPR, CO2-TPD, XPS, and in-situ DRIFTS revealed the preservation of a stable mesoporous structure, highly dispersed active species, regulated surface chemical properties, and a dominant formate-mediated reaction pathway. This study provided systematic experimental insights and theoretical guidance for the rational design of efficient CO2 methanation catalysts based on natural mineral supports.
Ultraviolet (UV) narrowband perfect absorbers based on metasurfaces have attracted significant attention for applications in sensing, spectral manipulation, and photonic devices. However, achieving multimode-coupled narrowband perfect absorptions in the UV regime remains challenging. Here, the simultaneous coupling of the second-order magnetic plasmon (MP) mode with both the Rayleigh anomaly (RA) and surface plasmon polariton (SPP) modes is realized in an aluminum metasurface composed of suspended U-shaped split-ring resonators. Dual narrowband perfect absorption is further achieved, originating from the MP–RA and MP–SPP coupling, respectively, with a maximum quality factor of 230. Furthermore, temperature-induced variations in the refractive index of ethanol enable continuous tuning of the dual absorption peaks, with temperature sensitivities reaching 0.12 nm/K and 0.11 nm/K. This work provides an effective design strategy for multimode-coupled UV perfect absorbers, holding promise for applications in spectral regulation and environmental sensing.
Tea plant (Camellia sinensis L.), one of the world’s most important beverage crops, is highly nitrogen (N)‑dependent. Soil N availability is therefore critical for tea yield, quality, and associated health functions. However, how the return of litter from periodic pruning affects soil N availability in tea plantations remains elusive. Here, pruned litter with typically high N content (22.2 g kg−1) was incorporated into rhizosphere and non-rhizosphere soils in tea plantations. Gross N transformation rates were quantified using a 15N dilution technique when considering two soils differing in pH (acidic vs. neutral) with three incorporation rates of 0%, 0.5%, and 1.0% (w/w). Our results showed that both net rates of N mineralization and nitrification gradually decreased with increasing incorporation rate, indicating a temporary soil N limitation under litter return. Such a limitation was more pronounced in neutral soil than in acidic soil, regardless of rhizosphere and non-rhizosphere. The underlying mechanisms for this limitation differed between these two soils. This was mainly attributed to a stronger stimulation of both ammonium and nitrate immobilization than N mineralization in acidic soil, but a decreased nitrification coupled with increased both ammonium and nitrate immobilization in neutral soil. Overall, our study demonstrated that inputs of N-rich pruned litter resulted in a lower soil N availability than previously thought. We thus recommend the co-application of chemical N fertilizer with pruned litter return in tea plantations to alleviate plant-microbe N competition.
As a zero-carbon carrier with high energy density, the efficient utilization of hydrogen is a key pathway for achieving deep industrial decarbonization. This urgently requires the synergistic conversion of chemical and thermal energy within a multi-energy complementary framework. This study proposes a novel combined power and steam system that couples a PEMFC with a flash heat pump. The system utilizes the pressure energy from the cathode exhaust to drive a turbine for auxiliary power generation and recovers the waste heat from both the anode and cathode exhausts to preheat the reactant gases. Simultaneously, the heat pump recovers the waste heat from the cooling channel, achieving internal energy cascade utilization through an economizer and a preheater. Furthermore, a cascaded optimization method integrating data-driven modeling, feature attribution analysis, and multi-objective decision-making is established to identify the system operating conditions. The results indicate that the coefficients of determination for the surrogate models all approach 1.00, verifying the high reliability of the data-driven approach in predicting the performance of the cogeneration system. Feature attribution analysis further indicates that the current and stack temperature show the highest relative importance for the power generation efficiency and cost distribution of the PEMFC, whereas the compressor discharge pressure and make-up water flow rate act as the primary factors influencing the heating capacity and economic performance of the heat pump. The case study demonstrates that under the selected operating conditions, the cogeneration system delivers 76.96 kW of net power and 390.92 kg/h of high-temperature steam, achieving a comprehensive energy efficiency of 0.89. Moreover, the LCOE for the PEMFC and the LCOH for the heat pump are reduced to $476.75/MWh and $1.32 × 10-2/kg, respectively. Consequently, the proposed method effectively bridges operating variables and performance indicators to trade-off energy efficiency and economic viability, thereby providing theoretical guidance for low-grade PEMFC waste heat cascade utilization and advanced cogeneration system development.
Green consumption constitutes a critical pathway to mitigating environmental threats and advancing carbon emission reduction. However, entrenched consumption habits and behavioral inertia often lead consumers to default to conventional products, creating a pronounced attitude-behavior gap in which pro-environmental attitudes fail to translate into actual purchases. To address this issue and uncover the dynamic mechanisms underlying consumer decision-making, this study draws on the Reflective-Impulsive Model (RIM) to develop a process model explaining how environmental concern (EC) influences green product purchasing (GPP). We introduce cognitive load (CL) as a moderator and examine the interventional effect of a default option (DO) as a nudging strategy. Using a 3 × 2 × 2 between-subjects experiment, the findings demonstrate that EC significantly promotes GPP. Reflective processing (RP) and impulsive processing (IP) jointly mediate the relationship between EC and GPP through dual pathways. CL weakens both the direct effect of EC and the mediating effect of RP. Moreover, DO effectively reduces consumers’ CL, thereby facilitating green consumption behavior. These findings offer actionable insights for online platforms and green enterprises seeking to promote sustainable consumption through nudging-based design strategies.
