RESUMEN
The commercial V2O5 -WO3/TiO2 (VWTi) catalysts often suffer from a serious joint deactivation by multiple heavy metals in the flue gas for NOx removal by NH3-SCR. Herein, we report an extraordinary deactivation offset effect between Zn and As on VWTi with alleviation of the toxic effects of the heavy metals by "like cures like". With the As&Zn content of 4 wt%, VWTi-As&Zn exhibited over 97% NO conversion under a GHSV of 100,000 h-1 and good SO2/H2O tolerance (> 93% NO conversion). It's presented 85% of fresh VWTi, exceeding those of VWTi-Zn (15%) by 5.6-fold and VWTi-As (70%) by 1.2-fold. Structure analysis showed that, unlike VWTi-As and VWTi-Zn, the VO vibration and dispersion state of VOx sites over VWTi-As&Zn were hardly affected. Moreover, VWTi-As&Zn possessed both the Lewis and Brønsted acid sites while VWTi-Zn and VWTi-As had only one type of them. The operando infrared/Raman/UV-vis spectroscopy and DFT calculations verified that the less affected VOx sites mainly reflected in three aspects: 1) the electron interaction between As and Zn; 2) the active VO Lewis acid sites; 3) lower energy barrier for N - H bond breaking. The "like cures like" phenomenon may open up an innovative pathway for the control of hazardous heavy metals.
RESUMEN
Background: Achieving climate targets will require a rapid transition to clean energy. However, renewable energy (RE) firms face financial, policy, and economic barriers to mobilizing sufficient investment in low-carbon technologies, especially in low- and middle-income countries. Here, we analyze the challenges and successes of financing the energy transition in Nigeria and Brazil using three empirically grounded levers: financing environments, channels, and instruments. Results: While Brazil has leveraged innovative policy instruments to mobilize large-scale investment in RE, policy uncertainty and weak financing mechanisms have hindered RE investments in Nigeria. Specifically, Brazil's energy transition has been driven by catalytic finance from the Brazilian Development Bank (BNDES). In contrast, bilateral agencies and multilateral development banks (MDBs) have been the largest financiers of renewables in Nigeria. Policy instruments and public-private partnerships need to be redesigned to attract finance and scale market opportunities for RE project developers in Nigeria. Conclusions: We conclude that robust policy frameworks, a dynamic public bank, strategic deployment of blended finance, and diversification of financing instruments would be essential to accelerate RE investment in Nigeria. Considering the crucial role of donors and MDBs in Nigeria, we propose a multi-stakeholder model to consolidate climate finance and facilitate the country's energy transition.