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CO2pre-injection during hydraulic fracturing is an important method for the development of medium to deep heavy oil reservoirs. It reduces the interfacial tension and viscosity of crude oil, enhances its flowability, maintains reservoir pressure, and increases reservoir drainage capacity. Taking the Badaowan Formation as an example, in this study a detailed three-dimensional geomechanical model based on static data from well logging interpretations is elaborated, which can take into account both vertical and horizontal geological variations and mechanical characteristics. A comprehensive analysis of the impact of key construction parameters on Pre-CO2based fracturing (such as cluster spacing and injection volume), is therefore conducted. Thereafter, using optimized construction parameters, a non-structured grid for dynamic development prediction is introduced, and the capacity variations of different production scenarios are assessed. On the basis of the simulation results, reasonable fracturing parameters are finally determined, including cluster spacing, fracturing fluid volume, proppant concentration, and well spacing. [ABSTRACT FROM AUTHOR]

Electrochemical nitrate reduction reaction (NITRR) has attracted much attention for yielding ammonia. Thus, it is of great significance to exploit new catalysts with a high nitrate-to-ammonia (NO3−-to-NH3) activity. In this study, we embedded different concentrations of Cu in an oxide octahedral molecular sieve (Cu(x)-OMS-1). We found that the Cu-dispersed OMS-1 optimizes the adsorption capabilities of the intermediates in NITRR and inhibits the competitive HER at a high current density. We reveal, using operando Fourier transform infrared spectroscopy and theoretical investigations, that the introduction of copper effectively promotes nitrate protonation during NITRR. Consequently, the catalyst presents the capacity for reducing nitrate to ammonia at a high current density (>100 mA cm−2) with ∼100% Faraday efficiency. The maximum NH3 partial current density reaches 148 mA cm−2 with a high production rate (0.69 mmol h−1 cm−2). [ABSTRACT FROM AUTHOR]

Lithium niobate (LN) is widely used in various optoelectronic systems due to its structural anisotropy and ferroelectric feature, which is one of the most essential platforms for next‐generation integrated optoelectronics. However, the insulating and optically transparent characteristics of LN have greatly limited the application in photodetection. Here, a high‐performance LN/WS2 based photodetector is achieved through a van der Waals integration strategy in which the pyroelectric property of LN and the moderate bandgap of WS2 are well combined. Upon light illumination, the light induced carriers in WS2 would increase and the pyroelectric charges of LN will cross the interfacial gap and asymmetrically inject into the WS2, creating an n−/n+ homojunction, thus improving the on‐state current. Under dark conditions, the sudden removal of the laser would introduce an instantaneous enhancement of polarization in the LN lattice, leading to an improved confinement on the remaining carriers in WS2, achieving a lower dark current. In this regard, the configurated device acquires a high on/off ratio more than 104 under zero bias, which represents the best among all the reported LN‐based photodetectors. This work realizes the complementary integration of 2D materials and ferroelectric LN and provides a feasible way for high‐performance photodetectors based on the LN platform. [ABSTRACT FROM AUTHOR]