Nine months after he came to power, Nigerian President Muhammadu Buhari received an official welcome from Qatar's Emir on Buhari's latest trip of many to boost Nigeria's standing abroad.The Nigerian president is seeking support for his crackdown on corruption and to encourage much-needed investment in his country's ailing economy.Qatar is the current president of Organization of the Petroleum Exporting Countries (OPEC) and Nigeria is Africa's largest oil producer.Low oil prices have a devastating impact on the Nigerian economy, which has long depended on the export of oil. 'We were unable to diversify our economy, hence we are much more disadvantaged by the lower oil prices,' Buhari says.Buhari tells us he values the institution of OPEC and that 'Nigeria will make the necessary sacrifice to remain in OPEC.'With a chorus of voices, including from the IMF, calling for the Nigerian government to devalue the naira, Buhari says he will not reconsider his insistence on freezing the currency. Buhari says as Nigeria 'virtually imports everything, from rice to toothpicks', it cannot afford to devalue its currency.'If it is against our national interest, why can't we go against the IMF advice' Buhari asks.Buhari's election campaign rode on pledges to root out corruption and quash Boko Haram. Yet, Boko Haram remains active in many areas of Nigeria, seemingly able to strike at will.And many questions are being asked about whether Buhari's anti-corruption drive is yielding results and if newer forms of corruption are emerging with a freeze on the naira.President Buhari talks to Al Jazeera about his campaign against graft and why he is adamant he hasn't failed in the fight against Boko Haram. He also explains why he believes the security of his country is best served by being part of the Saudi-led Islamic anti-terrorism coalition announced in December 2015.