It is not obligatory for a husband to pay zakaah on behalf of his wife, because zakaah is obligatory on the owner of the wealth. Zakaah is not part of the obligatory maintenance to which a wife is entitled from her husband.
With regard to a wife giving the zakaah of her wealth to her husband, many scholars have said that this is permissible, and they quote as evidence the report narrated by al-Bukhaari (1462) and Muslim (1000) from Abu Sa’eed al-Khudri (may Allaah be pleased with him), that when the Prophet SAWS (peace and blessings of Allaah be upon him) commanded the women to give in charity, Zaynab the wife of ‘Abd-Allaah ibn Mas’ood came to him and said: “O Prophet of Allaah, today you told us to give in charity. I have some jewellery and I want to give it in charity, but Ibn Mas’ood claims that he and his child are more deserving of my charity.” The Prophet (peace and blessings of Allaah be upon him) said: “Ibn Mas’ood has spoken the truth. Your husband and child are more deserving of your charity.”
This hadeeth indicates that it is permissible for a woman to give her zakaah to her husband. This is the view of al-Shaafa’i, al-Thawri and the two companions of Abu Haneefah. It was one of the two reports narrated from Maalik, and from Ahmad.
This is supported by the fact that the Prophet (peace and blessings of Allaah be upon him) did not discuss it further with her, which may be interpretted as meaning that his statement is applicable in general terms, because when she mentioned charity, he did not ask whether this was voluntary charity or obligatory charity (i.e., zakaah). It is as if he said: That is a valid action on your part whether it is obligatory or voluntary.
Some scholars said that it is not allowed for a wife to give the zakaah of her wealth to her husband, because he is going to spend some of it on her, so it is as if she is giving the zakaah to herself. They interpreted this hadeeth as referring to voluntary charity.
Ibn al-Munayyir responded to this view by saying: The possibility that her charity may come back to her also applies in the case of voluntary charity.
Shaykh Ibn ‘Uthaymeen said in al-Sharh al-Mumti’ (6/168-169):
The correct view is that it is permissible to give zakaah to one’s husband if he is one of the people who are entitled to zakaah.
Perhaps evidence for that may be seen in the words that the Prophet (peace and blessings of Allaah be upon him) spoke to Zaynab the wife of ‘Abd-Allaah ibn Mas’ood (may Allaah be pleased with them both): “Ibn Mas’ood has spoken the truth. Your husband and child are more deserving of your charity.” We may say that this includes both obligatory and voluntary (naafil) charity. Whatever the case, if this hadeeth is evidence then all well and good, but if it applies only to voluntary charity then with regard to giving zakaah to one’s husband we say: if the husband is poor then he is entitled to zakaah, and where is the evidence that this is not allowed? Because if the ruling can only be proven by evidence, there is no evidence either from the Qur’aan or the Sunnah that a woman cannot give her zakaah to her husband.
The Standing Committee (10/62) was asked:
Is it permissible for a woman to give the zakaah of her wealth to her husband if he is poor?
They replied: it is permissible for a woman to give the zakaah of her wealth to her husband if he is poor so as to ward off his poverty, because of the general meaning of the verse in which Allaah says (interpretation of the meaning):
“As-Sadaqaat (here it means Zakaah) are only for the Fuqaraa’ (poor), and Al-Masaakeen (the poor)”
The above applies only to a wife giving her zakaah to her husband. With regard to a husband giving his zakaah to his wife, Ibn al-Mundhir said: They (the scholars) are unanimously agreed that a man should not give his zakaah to his wife, because he is obliged to spend on her, which means that she does not need zakaah.